sperm

Polygamous deer mice have faster sperm

dr. dolittle — Thu, 27 Oct 2016 10:48:09 +0000

Polygamous deer mice have faster sperm

Image of a deer mouse from Seney Natural History Association, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=29576617

Deer mice are known for being quite promiscuous. In fact, it is not uncommon to find a litter of deer mice with multiple fathers. Dr. Hopi Hoekstra and colleagues at Harvard University's Department of Organismic and Evolutionary Biology discovered that the tail of deer mice sperm have longer midsections than found in monogamous mice. What this means is that their sperm can swim better and faster, thereby reaching an egg sooner than sperm from other prospective fathers. The research team identified the gene responsible for producing the olympic-sperm, PrKar1a. The findings from this study may also help improve human fertility since other research suggests this same gene might be involved in human fertility.

Source:

Fisher HS, Jacobs-Palmer E, Lassance J-M, Hoekstra HE. The genetic basis and fitness consequences of sperm midpiece size in deer mice. [pre-print from BioRxiv] doi: http://dx.doi.org/10.1101/077826

dr. dolittle Thu, 10/27/2016 - 06:48

Tags

Life Science

deer mice

fertility

sperm

No, cell phones are not "cooking men's sperm"

oracknows — Wed, 24 Feb 2016 08:00:47 +0000

No, cell phones are not "cooking men's sperm"

I've written several times over the years about the overblown claims of harm attributed, largely—but not exclusively—by cranks, to cell phone radiation. It's been claimed that radiation from cell phones can cause brain tumors (there's no convincing evidence that this is true), breast cancer (the evidence for these claims is so incredibly flimsy—and featured by Dr. Oz, to boot!—that this is not a credible claim), and a wide variety of other health issues. Indeed, if you believe the cranks, the mobile phone companies are the equivalent of tobacco companies denying that their products cause massive harm.

Never mind that, based on pure physics alone, it is incredibly unlikely that radio frequency radiation can cause cancer. I've described it many times, but it's always worth describing again. This particular form of radiation is just too low energy to break chemical bonds in DNA, a prerequisite for most mutations. On the other hand, a lot of the debunkings of the claimed cell phone-cancer link often rely on what I like to refer to as a "Cancer Biology 101" understanding of how cancer develops in which DNA strand breakage is an absolute requirement for the development of cancer, and I've gotten into trouble for being more open to the possibility that there might actually be a plausible biological mechanism by which cell phone radiation might cause cancer. (Usually, it's physicists, hence the "Cancer Biology 101" understanding.) As I like to say whenever this topic comes up, it is highly implausible based on basic science that cell phone radiation could cause cancer. It’s not homeopathy level-implausible, but it’s pretty implausible. Nor is it impossible, as has been claimed, because there may be biological mechanisms behind cancer that we do not yet understand, and it’s almost always physicists with little knowledge of epigenetics and other mechanisms of cancer development who make such dogmatic claims. Absent compelling evidence of a link between cell phones and cancer, then, it is not unreasonable to rely on the basic science and consider the possibility of such a link to be remote.

Although I've dealt with the issue of cell phones and cancer time and time again, it occurs to me that I haven't dealt with another claim frequently made about adverse health events due to cell phone radiation, namely that it's deadly to our ~~vital essence~~ sperm. The other day, I saw a ridiculously fear mongering article in The Telegraph entitled Mobile phones are 'cooking' men's sperm:

Fertility experts are warning man that using a mobile for as little as an hour a day is "cooking sperm" and lowering level significantly.
The new study shows that having a mobile phone close to the testicles - or within a foot or two of the body - can lower sperm levels so much that conceiving could be difficult.

The findings have led to a leading British fertility expert to advise men to stop being addicted to mobile phones.

The study - by highly respected specialists - found that sperm levels of men who kept their phones in their pocket during the day were seriously affected in 47 per cent of cases compare to just 11 per cent in the general population.

Professor Martha Dirnfeld, of the Technion University in Haifa, said: "We analysed the amount of active swimming sperm and the quality and found that it had been reduced.

"We think this is being caused by a heating of the sperm from the phone and by electromagnetic activity."

What utter rot!

This is irresponsible journalism (and science communication, to boot—I mean you, Prof. Dirnfeld!) at its worst. Basically, the message is: Hey, you men! Stop being addicted to your mobile phones! They're ~~sapping your precious bodily fluids~~ frying your sperm! Stop being so into your cell phone, you idiots! Of course, that might not be such bad advice, but why it might be reasonable advice has absolutely nothing to do with sperm counts, sperm motility, or infertility. If it's good advice, the reason has more to do with being less obsessed with a handheld device and more interested in what's going on around oneself.

Whenever I see an article like this, I always have to go straight to the study. That proved to be harder than usual, which lead me to curse journalists for not providing direct links, DOI numbers, or even formal references to studies that they report on. Eventually, I did find the paper. It's an article in Reproductive BioMedicine Online by Zilberlicht et al, entitled Habits of cell phone usage and sperm quality – does it warrant attention? At this point, I was tempted to invoke Betteridge's Law of Headlines and leave it at that, just answering no, but I'm a glutton for a study, even a bad one. It's one of my blogging specialties.

So what about the study? Let's just say that the abstract is not promising:

Male infertility constitutes 30–40% of all infertility cases. Some studies have shown a continuous decline in semen quality since the beginning of the 20th century. One postulated contributing factor is radio frequency electromagnetic radiation emitted from cell phones. This study investigates an association between characteristics of cell phone usage and semen quality. Questionnaires accessing demographic data and characteristics of cell phone usage were completed by 106 men referred for semen analysis. Results were analysed according to WHO 2010 criteria. Talking for ≥1 h/day and during device charging were associated with higher rates of abnormal semen concentration (60.9% versus 35.7%, P < 0.04 and 66.7% versus 35.6%, P < 0.02, respectively). Among men who reported holding their phones ≤50 cm from the groin, a non-significantly higher rate of abnormal sperm concentration was found (47.1% versus 11.1%). Multivariate analysis revealed that talking while charging the device and smoking were risk factors for abnormal sperm concentration (OR = 4.13 [95% CI 1.28–13.3], P < 0.018 and OR = 3.04 [95% CI 1.14–8.13], P < 0.027, respectively). Our findings suggest that certain aspects of cell phone usage may bear adverse effects on sperm concentration. Investigation using large-scale studies is thus needed.

Wow! Sounds damning, doesn't it? Well, on the surface it does. Let's dive deeper, as I am wont to do with studies like this.

First of all, let's look at the central hypothesis, namely that cell phone radiation causes decreased sperm count and motility, both of which are associated with male factor infertility, for obvious reasons. There's only one plausible biological mechanism (and, even then, it's not so plausible) to explain how cell phone radiation might decrease sperm count and motility. After all, it's well known that increased temperature is associated with decreased sperm count and quality. It's the very reason that fertility doctors recommend that men being evaluated for infertility wear boxers instead of briefs.

So what about this study?

One thing I noticed is that the study in question was published in September 2015. This lead to me wonder: Why is there news coverage of this paper now, given that it was published nearly six months ago? I can only speculate that some editor somewhere was looking for a story and heard about this. (I mean, come on. Who can resist a headline like Great balls of fire! Mobile phones are ‘cooking’ men’s sperm?) I don't know about Martha Dirnfeld, but if someone called me about a paper I published in February, I'd wonder what was going on, although I'd probably appreciate the attention and cooperate the way that Prof. Dirnfeld did.

The study itself is fairly unremarkable. It is an unrandomized study of men presenting to Carmel Medical Centre for a first time semen analysis as part of an infertility workup. So right there, we know that this is not a representative sample of men. There is no "normal" control group because all of these men were being evaluated for male factor infertility. The study is a relatively small one, only 106 men, of which 26 men were excluded because they didn't meet the study criteria, which means only 80 men were analyzed. Here are the things they were asked about:

This included questions regarding their demographic background, i.e. age, place of living, number of children, occupation, ethnicity and educational status. There were also questions on their general medical history and fertility-related conditions (i.e. varicocele, orchitis), as well as lifestyle habits such as smoking and consumption of alcohol. Further questions accessed information about daily habits of cell phone usage such as the number of devices used and the duration of daily use (talking). The latter was classified by four categories: less than 30 min, 30–60 min, 60–120 min and over 120 min. The usual location of the device while talking, carrying and charging was assessed separately.

And:

Data regarding the use of accessories such as hands-free devices and earphones were collected as well. Other variables included the number of years that an individual owned a cell phone, talking while the device is being charged (as a categorical yes/no question) and talking in low reception areas (defined as: elevators and underground floors). Information on cell phone types, models and frequencies was not collected.

So right away, I see a number of problems. First, not collecting information on cell phone types is a big issue, as different models emit different amounts of radiofrequency radiation. A more problematic issue is a major assumption behind the study, specifically that time spent talking on one's mobile phone correlates with exposure of a man's genitals to the evil magic radio waves. First, even though the data for this study were collected in 2011 and 2012 (one wonders why it took so long to analyze the data, given that this was a prospective study), by then, time spent speaking arguably no longer represented a good measure of cell phone use by then. After all, the iPhone 4 was released in 2011. A better question would be how long one is on one's mobile phone, either speaking or surfing the Internet. I don't know about you, but I hardly ever use my iPhone for telephone conversations any more; at least 90% of its use is to access the Internet.

There's another problematic issue with this study. I don't know about most men, but when I'm using my phone, be it to have a conversation, to text, or surf the Internet, it's nowhere near my family jewels, if you know what I mean. Even so, these results are far from convincing. For example, there are a lot of unimpressive p-values here. The finding that talking duration of more than one hour per day was associated with a higher rate of abnormal sperm concentration than talking less than one hour per day resulted in a p<0.04, which probably means it was between the p-value between 0.03 and 0.04, because otherwise the authors would have reported p<0.03.

Then there's the issue of univariate versus multivariate analysis. Whenever you examine multiple variables for their potential correlations with various outcomes, you'll run into the problem of multiple comparisons, where, the more variables you examine the greater the chance of seemingly "positive" results by random chance alone. That's why Student's t-test is not appropriate for multiple comparisons, for example, and it's why univariate analysis is fine for an initial exploration of multiple variables but has to be followed by an analysis that takes multiple comparisons into account. And, as you see in the abstract above, there were only two things that came out as statistically significant: talking while charging the device and smoking, both of which were associated with abnormal sperm concentration.

Then there was another finding that is basically meaningless. Basically, among men who reported holding their phones ≤50 cm from the groin, the "rate of abnormal sperm concentration showed a non-significant trend towards a higher value among participants who reported generally keeping their cell phones at a distance ≤50 cm from the groin compared with those who kept it at a distance >50 cm from the groin (47.1% versus 11.1%). No association was found between any of the factors investigated and between semen volume and progressive motility (data not shown)."

In other words, the authors were really, really, really stretching to eke out a seeming correlation relevant to a link between cell phones radiation and decreased sperm count and male factor infertility. Heck, there wasn't even a correlation between keeping the phone near one's testicles and...anything examined! Basically, this study is nonsense, and the authors do a serious song and dance to try to make statistically insignificant findings sound important:

The participants in this study, who reported talking on their phones while the device was being charged, were more likely to have abnormal semen concentration. To our knowledge, this aspect of cell phone use has not been previously addressed. During charging of cell phones, two changes occur: (i) the external power source by itself emits energy; and (ii) due to the continuous supply of energy from the external source, the device transmits at a higher power, without the need for energy saving, in contrast to the usual talking mode.

None of which was measured. And:

Participants who constantly carry the device at a distance ≤50 cm from the groin were found to have a higher rate of abnormal sperm concentration. Although the association did not reach statistical significance, it appears that sperm parameters may be affected, even during a stand-by mode (when RF-EMR is emitted from the device for short durations).

Huh? No it doesn't. Your data didn't reach statistical significance, and we have no idea what you mean by "approaching" statistical significance! How close was your p-value to 0.05? If you're serious about arguing that there is an effect but that your sample size was just too small to detect it, you really should give the actual p-value, rather than just "NS" for "not significant." Such an argument tends to be a lot more convincing if p=0.06 than it is if p=0.25. I'm by no means a p-value Nazi (if I were, I wouldn't be so much into science-based medicine rather than evidence-based medicine), but I also realize that "approaching statistical significance" usually means, "no matter how much we tortured the data we just couldn't make the p-value fall below 0.05."

Basically, if you look critically at the data, one thing that becomes very clear is that the studies purporting to show a link between cell phone radiation and male infertility are uniformly horribly designed and unconvincing. This one is no exception. The Telegraph published a rebuttal article that's not bad, but still leaves something to be desired. First, it quotes experts correctly pointing out just how bad these studies are. Second, it quotes Allan Pacey, Professor of Andrology at the University of Sheffield:

"What is more of a problem is men - and couples - waiting until they are older before they are trying for a baby and then trying to blame their infertility on things like mobile phones when it’s their combined age which is probably a bigger problem."

Yes. This is very likely a factor. Unfortunately The Telegraph couldn't resist going here:

Pacey's opinion - that mobile phone radiation is being seized upon by infertile men as a convenient scapegoat for their condition - is supported by Stephen Harbottle, a Consultant Embryologist at Cambridge IVF.

"There are a number of environmental factors that may be contributing to the general decline we have seen in male fertility over the last 15 years," says Harbottle, who believes mobile phones are much further down the list of causes than recent research would have us believe.

"Probably most significant factor is oestrogen-mimicking compounds in the food chain. These can enter the food chain via pesticides and some plastic food wrappings.

You knew it wouldn't be long before they brought pesticides and BPA into it. There really isn't any good evidence to support this assertion.

The bottom line is that cell phone usage as measured by a study like the Technion study is almost certainly a confounder, a surrogate for some other factor that is known to be related to infertility that the study doesn't control for. By reporting a small, crappy study like this as evidence that cell phones are "cooking men's sperm" journalists exercise the very worst tendencies in science reporting, tendencies that I've railed at since the beginning, particularly when it comes to vaccine reporting.

For shame, anyone who credulously swallowed this story and ran with it.

oracknows Wed, 02/24/2016 - 03:00

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Clinical trials

complementary and alternative medicine

Skepticism/Critical Thinking

cell phone

Infertility

male factor infertility

complementary and alternative medicine

medicine

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Physical Sciences

Unless, of course, you are applying your smartphone (certain brands/models can get incredibly hot at times) directly to your scrotum...

Yeah, I resisted the temptation to make that particular joke. Maybe I shouldn't have. :-)

Eureka! The male birth control method we've been searching for all these years! And right there under our noses (in our pockets?) all this time.

Next time Mr. Lapdog calls me I will be sure to enquire whether the phone is 50 cm from his junk. (Unless your guy is a hobbit, I can’t imagine this is an issue).

Thanks for the crap study deconstruction tutorial, Orac.

I'm with Janet @ 3. Damn, too bad for the study.

But one can't help wonder if some minor tweak to the hardware could make it so. 7 billion heading for 9 billion on a planet that can sustainably support 3 billion at European standards of living, makes it imperative to find new methods of birth control that people will find irresistible.

OTOH, video games. "Not tonight, honey, I'm right in the middle of shooting zombies!"

@Orac...I know you frown on typo comments, but I have to admit this one made me laugh...." ...time spent talking on one’s mobile home...

The visual is hysterical.

As I've said many times before ( in regards to blaming autism on vaccines), it makes people feel better to attribute negative outcomes to external causes:
they would rather blame a phone than the fact that perhaps they are not longer the young dudes** bursting with procreative power that they once were ( at least in their imaginations) or that there is something ELSE wrong with them.

** we all forever indebted to David Bowie for that song and that phrase.

I wonder if they checked to see if subjects were using their phones for "inappropriate internet research," especially prior to sample collection?

@ Gray Squirrel:

You know, I've heard it remarked ( perhaps as a joke) that low birthrates in Japan can be blamed on manga and anime as well as video games.

I'm sure we can find other modern technologies to blame in post-industrial cultures- virtual reality will certainly be indicted when it becomes as widespread as internet pornography.

I remind those who hold that strands of genetic material can't act as an antenna that a discontinuity within a dielectric does indeed act such:

Most of what we know about electromagnetic radiation comes from theories first proposed by James Clerk Maxwell in the 19th century, which state that electromagnetic radiation is generated by accelerating electrons. …

… However, this theory becomes problematic when dealing with radio wave emission from a dielectric solid, a material which normally acts as an insulator, meaning that electrons are not free to move around. Despite this, dielectric resonators are already used as antennas in mobile phones, for example.

“In dielectric aerials, the medium has high permittivity, meaning that the velocity of the radio wave decreases as it enters the medium,” said Dr Dhiraj Sinha, the paper’s lead author. “What hasn’t been known is how the dielectric medium results in emission of electromagnetic waves. This mystery has puzzled scientists and engineers for more than 60 years.”

http://phys.org/news/2015-04-electromagnetism-enable-antennas-chip.html

and

The microwave absorption is directed by the dielectric constant of the tissue. At 2.5 GHz, this ranges from about 5 for adipose tissue to about 56 for the cardiac muscle. As the speed of electromagnetic waves is proportional to the reciprocial value of the square root of the dielectric constant, the resulting wavelength in the tissue can drop to a fraction of the wavelength in air; e.g. at 10 GHz the wavelength can drop from 3 cm to about 3.4 mm.

http://en.wikipedia.org/wiki/Microwave_burn#Frequency_vs_depth

Now add harmonics, considering the whole sack to be in the phones near field, it seems plausible that appreciable amounts of jitter can be imparted into the sperm's jiggly bits -- Crashing the cymbals onto the cartoon characters' head does not immediately cause cancer to spring forth either; But he does walk around kinda funny for a little while.

Shouldn't it be easy enough to test for some effect directly? Dap a little dab on a slide and observe it under a microscope while MMS'ing cat pics to the entire department one at a time.

Some studies have shown a continuous decline in semen quality since the beginning of the 20th century.

Not the best intro for a treatise on mobile phones or a shocking lack of historical knowledge.

A mobile phone, or possibly telegraph, in about 1915 consisted of, IIRC, a large wagon with a big roll of copper wire, 7 horses, and 9 men according to the Canadian military's communications museum's display on laying field communications.

Oh and presumably a telephone.

As I’ve said many times before ( in regards to blaming autism on vaccines), it makes people feel better to attribute negative outcomes to external causes:
they would rather blame a phone than the fact that perhaps they are not longer the young dudes** bursting with procreative power that they once were ( at least in their imaginations) or that there is something ELSE wrong with them.

Yes, this. I used to moderate a message board for AMA women trying to conceive. I saw this all of the time. The age at which female fertility begins to decline tends to be poorly understood and frequently underestimated, and acknowledging that it might be too late can be extremely hard. Harder than blaming cell phones, BPA, "toxins", etc.

citation http://www.npr.org/assets/news/2011/11/FertilityWhitePaper_Final.pdf

Notice the samples were collected in September. Sperm production and maturation takes a few weeks to a few months. A few months after heat waves, sperm quality in male livestock can drop very far. I would assume the same mechanism could cause sperm quality to drop in human males as well.

The difference between men may be low quality sperm in men who worked outside and thus may have spoke on a cell phone for an hour compared to men who worked indoors with AC and used a hard wired line to talk instead.

certain brands/models can get incredibly hot at times

This is actually a physically plausible mechanism: as I understand it, excessive heat around the scrotum tends to reduce sperm counts. Of course, baking the family jewels doesn't sound nearly as scary as zapping them with the evil RF. And the study result is null, so it hasn't been established that there is a problem that requires an explanation.

I don’t know about most men, but when I’m using my phone, be it to have a conversation, to text, or surf the Internet, it’s nowhere near my family jewels, if you know what I mean.

I don't either, but you and I are old-fashioned in this regard. Plenty of people use earbuds, or Bluetooth headsets, with their phones. I sometimes joke that I am old enough to remember a time when you could assume somebody who was walking down the street and apparently talking to himself was crazy--these days, the person might simply be using the phone.

Rats. Back to punching myself.

Delphine: What do you mean by the 'The age at which female fertility begins to decline tends to be poorly understood and frequently underestimated?" At twenty-five, women peak, right? At least, that's what I understand from every mothering board and dating site i've ever lurked on.

@Eric #14

I've learned that the absolute foolproof, copper-bottomed way to avoid being approached on the street is to participate in the "Say Something In Welsh" audio course. It's all listen and repeat exercises. Combining "Nac ydw, dw i'n ddim yn hoffi cwrw"* and a military surplus winter coat usually guarantees a quiet train ride home...

*"No, I don't like beer."

I mean that from what I've witnessed, a great many women fail to understand and/or dismiss the effect of age on fertility, and underestimate the age at which fertility begins to decline.

I'm 44. I had my daughter at 40, after a long struggle with infertility and infant loss, and after blowing a not-insignificant wad of cash on ART. Because I was old. There was no other reason. I heard and continue to hear stuff like this all of the time. http://www.npr.org/2011/12/01/142725547/many-women-underestimate-fertil…

Delayed childbearing, the whys and wherefores, they are sticky, difficult issues.

"is" a sticky, difficult issue.

Delphine: I mean that from what I’ve witnessed, a great many women fail to understand and/or dismiss the effect of age on fertility, and underestimate the age at which fertility begins to decline.

I’m 44. I had my daughter at 40, after a long struggle with infertility and infant loss, and after blowing a not-insignificant wad of cash on ART. Because I was old. There was no other reason. I heard and continue to hear stuff like this all of the time.

Ah, okay. I think part of the difficulty is the media. Women are always hearing 'after twenty-five/thirty/ thirty-five' you can't have babies anymore,' and many women know mothers who have had kids after those milestones, and then proceed to just tune out.
For instance, my mom had me at thirty, and my brother at thirty-five, so I know it's possible. Though, no disrespect, but motherhood isn't feasible for me or my sister. We're too poor to raise kids.
Which is another problem- women spend their twenties and thirties getting financially established, and only amass enough wealth by their forties.

Ah, okay. I think part of the difficulty is the media. Women are always hearing ‘after twenty-five/thirty/ thirty-five’ you can’t have babies anymore,’ and many women know mothers who have had kids after those milestones, and then proceed to just tune out. It's that, but it's also the opposite - stories about celebrities, for example, who have children in their 40s, without any corresponding dialogue of what it might have taken to get there, or how many others tried, failed, or are still trying. There's this whole "40 is the new 30" and the thing is, your ovaries don't give a rat's that you do Pilates and love Arcade Fire.

For instance, my mom had me at thirty, and my brother at thirty-five, so I know it’s possible. To extend that thought, women throughout history have routinely given birth well into their 40s. That factoid gets pointed out a lot with respect to delayed childbearing. What gets ignored there is that these women having children in their 40s typically weren't having their first child.

Which is another problem- women spend their twenties and thirties getting financially established, and only amass enough wealth by their forties. Yeah, I dunno. I have mixed feels about that rationale, but I said "sticky" and that one is, so...part of the problem is that it's now almost taboo for women to have children when they are actually in or around their reproductive peak years.

@Johanna - I've met several people from Wales. Based on what I've seen, the phrase "Nac ydw, dw i’n ddim yn hoffi cwrw” has never been said by a native speaker, and is a phrase without meaning.

"During charging of cell phones, two changes occur: (i) the external power source by itself emits energy; and (ii) due to the continuous supply of energy from the external source, the device transmits at a higher power, without the need for energy saving, in contrast to the usual talking mode."

This is absurd.

The "external power source" is at worst an exceptionally low power emitter of RF at HF and lower frequencies (much lower energies than cell phone transmissions), usually due to their use of switching power supplies.

Recent generation cell phones do not adjust power based on battery level or DC supply. Power is in general negotiated with the base station to the minimum required for reliable communication.

Cell phones are safe?
What do doctors know anyway! OT but it's late

Today, Mikey ( Natural News podcast- now we can hear him as well as read his tripe)
asserts that doctors are "idiots" because they don't know that vitamin D and lack of sunscreen work against cancer.
Nutrition is the answer and sceptics are "dinosaurs": they know nothing.
So don't listen to them, listen to Mike ( and NDs and CAM )

This 21 minute rant is amongst Mike's finest. First rate.

-btw- I know how to say sh!t in Welsh but I can't spell it.

[parody] So says the phonema-shill!
If there was nothing to this, why is Donald Trump investing into Gallinger Enterprizes, a firm cornering the sales of cheap burners in poor African-American and Latino communities, via aggressive street-level marketing of its U-Gen brand phones? "'Forget Next-Gen. Go U-Gen!"
[/parody]

Delphine: …part of the problem is that it’s now almost taboo for women to have children when they are actually in or around their reproductive peak years.

Yeah, that is a sticky one. Women have to choose between education and family, and no one really wants to choose to be poor. In theory, there ought to be some way to solve the problem, but it'd take a drastic reengineering of society and human men.

Recent generation cell phones do not adjust power based on battery level or DC supply. Power is in general negotiated with the base station to the minimum required for reliable communication.

I figured as much, but was that true in 2011-2012, when the data were collected for this study? (The iPhone 4 was released in October 2011.)

Cell phones and cancer are my go-to counterargument when arguing with anti-GMO types, when they say things like, "Even if there is no evidence now, we don't know what will happen in 10 more years, so it's best to be safe and just not consume them at all."

The point being, it is funny how people suddenly start trusting science when it tells them something that benefits them personally. It's easy to be anti-GMO when you have a secure food supply and nothing at stake, but when it comes to my cellphone, well, that's different.

Of course, this blog entry shows us that the truly delusional are bound to distrust science no matter what the cost. But there are a lot more anti-GMO people than anti-cellphone people.

@MoB

True that. I should have said Bovril or something. :)

(I, personally, don't like beer, but for complicated reasons)

Yeah, that is a sticky one. Women have to choose between education and family, and no one really wants to choose to be poor. In theory, there ought to be some way to solve the problem, but it’d take a drastic reengineering of society and human men.

I hear you, but I think that's an oversimplification. The sucky reality is that we have a limited window, there is only so much reproductive medicine can do, and we need to prioritize accordingly. And I know that rubs a lot of people the wrong way. But I do think women and men equally need better/more education on fertility/reproduction as a whole.

Only deniers would deny that there is a correlation between cellphone use and infertility.

For instance, it was reported in a Major Newspaper earlier this week that the average smartphone user spends 3 1/2 hours per day using cellphone apps.

Add in all the time people spend yakking on their cellphones or just staring in fascination at the screen while walking into walls, and that's time unavailable for procreation.

Do the math (or maths, as the Brits would say).

"I figured as much, but was that true in 2011-2012, when the data were collected for this study? (The iPhone 4 was released in October 2011.)"

Even longer. It's not strictly a phone issue but the underlying radio technology, and compliance to relevant standards. The iPhone is no different in that it uses radio chip sets that are compliant (must comply by regulation). Non-compliant chip sets/devices would either not work or incur a serious regulator response. Excess power from a phone degrades service to other subscribers, whether used for administration comms, voice or data.

I was so glad to see Orac make a point I noted myself when reading the original news article. How does it make any sense that more time spent talking on a cellphone correlates with more sperm damage, if presumably you don't talk from your scrotum? If anything, you'd see the opposite correlation - the less people actually use their phones, the more damage you'd see. It's nonsensical.

A few years back there was an article in an Israeli paper about a fire/explosion at a gas station. The headline shouted about how a woman's cellphone caused the fire, and spent paragraphs and paragraphs giving warnings and quoting experts on how you shouldn't use cellphones in a gas station...

...and then, in the very last paragraph, mentions that witnesses said the woman was not using her cellphone at the time of the fire.

For instance, it was reported in a Major Newspaper earlier this week that the average smartphone user spends 3 1/2 hours per day using cellphone apps.

Add in all the time people spend yakking on their cellphones or just staring in fascination at the screen while walking into walls, and that’s time unavailable for procreation.

This inspired my new New Year's resolution - to spend that 3 1/2 hours a day on procreative activities. Wish I'd thought of that back in college.*

* Well, actually I thought of it quite a lot in those days before cell phones, but had problems with finding other willing participants. That and chafing.

Did the study account for the phone being on ring or vibrate as a variable?

Ah, okay. I think part of the difficulty is the media. Women are always hearing ‘after twenty-five/thirty/ thirty-five’ you can’t have babies anymore'

It is my understanding, PgP #20, that a girl/woman is born with all the eggs she will ever have and that those eggs are degraded over time due to environmental toxins, disease, and radiation to include cosmic rays. For this reason alone is it more desired for a woman to bear children at a younger age -- For instance, Mary was 12 when God knocked her up.

If cellphone signals damage the DNA strands in rapidly-dividing cells, hair follicles are also at risk.
Cellphones made me bald!

If this were true, then this person would be Sterile Erol with the Cool Tool : http://www.nydailynews.com/news/world/man-caught-38-cell-phones-stuffed…

I'm always amused when people very emphatically insist that cell phones can't cause cancer because RF waves can't break DNA. I agree that cell phones probably don't cause cancer - the sheer number of cell phone users today, without a corresponding spike in any any kind of cancer, implies the risk must be small if it even exists.

That said, as Orac states, breaking DNA is not the only way for something to be carcinogenic. Mutations are a part of every cancer, but the carcinogenic agent need not cause those mutations directly. The carcinogen could be an irritant that increases cell turnover, or inhibit the function of cellular mechanisms that monitor or repair naturally occurring mutations.

Proteins contain charged particles, so must have some kind of response to any passing EM wave. One could imagine such a wave changing things like reaction constants or the energy of different folded states. And something like this could, in theory, irritate a cell or inhibit the mechanisms to repair mutations. Possible? Sure. Plausible? Ehhh, probably not, since the epidemiology kind of sets a low upper bound on how bad this could possibly be. But Orac is exactly right - this is not "homeopathy levels" of implausible.

Someone mentioned cell phone usage being a confounder for the type of job someone has. I hadn't thought of this before, and it makes sense. I'd be surprised if cell phone usage *didn't* correlate with something like type of job, indoor vs. outdoor job, frequency of traveling, time spent sitting down, etc. Any of those things is a more plausible cause of sperm abnormalities.

And anyway, just like the case with cell phones causing cancer, the fact that going from no one having a cell phone to almost everyone having a cell phone in just 30 years, without fertility rates falling through the floor, sets a pretty strict bound on how bad they can be for our swimmers.

herr doktor bimler is correct:
I hardly use a cell phone and I have hair.

Perhaps we should it write up and submit it to Medical Hypotheses. At least we have N=2.

write it up

One of my brothers has a cell to his head all the time and is bald. I am 6 years older and don't use a cell phone much and have a full head of hair.

We only need 100 more respondents and we can equal the above study and not be able to prove anything.

I have to say I'm terribly amused at this silly study because I used the opposite argument on why cell phones are safe.

To wit: A friend was describing an app for a smartphone that monitors your sleep to help you wake up during the 'light' part of your sleep cycle. In order to work, you put the phone under your pillow. The friend's sister was aghast at keeping your phone by your head for so long, that it was dangerous. My argument was that clearly phones that weren't being used as phones were safe because we *hadn't* seen a major fertility drop off.

Proteins contain charged particles, so must have some kind of response to any passing EM wave.

I'm on hold with somebody, but you might want to look here.

@ Dangerous Bacon

Add in all the time people spend yakking on their cellphones or just staring in fascination at the screen while walking into walls, and that’s time unavailable for procreation.

You are assuming those people will not have found something else to do aside sex. Or to put in another way, that romance was an option in the first place.
You could remove every electronic devices to a freak like me, I will still be fully unable to go talk to the nice girl next door.
OTOH, I have this feeling that don juan wannabe have no trouble fitting their phone use in their sex life.

Helianthus @45: And has anyone done a study on the sperm motility in the guy who are swiping on Tinder to find a woman to have sex with while actively engaged in sex with another women? (As has been reported in Vanity Fair in a lovely article on how broken all Millennials are.)

"herr doktor bimler is correct:
I hardly use a cell phone and I have hair."

herr doktor bimler is fibbing; he is well-endowed in the hair department :P

@ Alison:

I know I saw his photo but I couldn't forego the chance to insult MH.

sperm motility in the guy who are swiping on Tinder to find a woman to have sex with while actively engaged in sex with another women

Being kicked in the goolies is a kind of sperm mobility.

Obviously Professor Dirnfeld is a shill for the Faraday-Caged Underpants industry:
http://www.lessemf.com/personal.html#261

Oh please, Thackeray never wrote anything of the sort!
---

Okay, sorry, I'll get my coat.

Oh please, Thackeray never wrote anything of the sort!
Perhaps Helianthus was thinking of works by Trollop.

insert Dickens joke here :)

re low Japanese birth rates: Look up the Japanese "herbivore men"-phenomenon. Due to social pressures and cultural norms that are very prevalent in Japan, young Japanese men are "checking out" of society and refusing to get married and have children - which has been disastrous to their birth rates.

https://en.wikipedia.org/wiki/Herbivore_men

It is what has spawned and influenced the "Men Going Their Own Way" (or MGTOW) movement in Western Culture.

Perhaps Helianthus was thinking of works by Trollop.

More on the line that with my level of social life, I don't have much use for my gonads, so this whole cell phone scare is just wizzing way over my head.

Look up the Japanese “herbivore men”-phenomenon

The parallels with western societies are interesting. A decade back, an article I read was talking how a good chunk of the the recent generations were putting themselves in stasis - staying longer at their parents' place, waiting more to set down and have children, and so on -, and in short bemoaning a lack of role models.

In my circle of friends, staying at home at 25-30 years of age is the norm not the exception. Difficulties finding a decent job as well as lack of housing opportunities has wrecked havoc on my generation; we're basically living as teens with our parents for almost twice as long as we should...

@ Amethyst

Yeah, speaking for myself, it's more than "I'm afraid of women". Scarred of long-term relationship is more like it, to start with (i.e. the problem starts with me - I have to go past the feeling that I'm not good enough). Job stability is a huge factor, too.
I didn't care much for the MGTOW analysis on wikipedia linking the phenomenon with "feminist laws". Social pressures on men to be masculine, successful and married (or whatever else they are supposed to be) doesn't just come from "feminazi".
Actually, this traditional role model for men is deeply linked with a, well, traditional view of a patriarchal society - like the Japanese society -, so quite the opposite of feminist views, but what do I know?

Third wave feminists and MGTOWs are pretty much the same in the sense that they do occasionally raise some good points, but on the whole they're letting their ideological bias taint their views to such a degree that they're no longer based in reality.

On the feminist side you have blatant falsehoods such as rape culture and the gender pay gap - neither of which exists outside of feminst twisting of statistics.

On the MGTOW side you have all kinds of absurdities, such as the vagina injecting a mind-controll substance into the penis (no doubt via vagina dentata!) during intercourse.

But you shouldn't look to MGTOWs for a perspective on male issues on society - a lot of them are bitter and hateful towards women because they've been hurt (there is a reason they "Went their own way" after all). The MRM (Men's Rights Movement) is a much more apt "adversary" to feminists, and I find myself sympathizing with their views a lot (such as men facing much longer prison terms for the same crime as a women, and custody unfairness).

I'm going to step in right here and point something out. This post is not about feminism. Consequently, I would very much prefer that it not devolve into a flame fest about feminism. The last few comments make me worry that we're on the verge of seeing that happen.

Well, since that was obviously aimed towards me, I can assure you I don't intend for it to go down that route at all.

I also can't help but feel slighted, since I am pretty sure I've been as respectful on the subject as one can be. I don't agree with you on that the "last few comments" have been bad. Hmpf.

Sorry, being caught in my own wool gathering.
Apologies for any offensive comment. It was not intended as much.

"as such."

OK, coffee time, brain is misbehaving more than usual..

Preemptive strike. I've seen this happen too many times before on other discussion forums, regardless of how seemingly respectful it starts out. I was starting to get a bad vibe about the way this was going. So I intervened. It also didn't help that the thread was going way off topic.

Considering the subject at hand (aided by the very first comment by yours truly) do we really want it to stay on topic?

Hahaha!

Denice Walter #24 it's spelt "cachu".

Joanna #17, you're more likely to hear "Na, nid wyf yn hoffi cwrw" without contraction or "Na, nid wy'n hoffi cwrw" with contraction. The latter being commoner, especially when spoken. Though unless replying to an offer of a beer, the "Na" would also be left off if simply stating that one doesn't like beer.

Orac's house, Orac's rules. :)

Computers can't own real estate, silly.

" Orac's house, Orac's rules"

I'm glad of that because I won't be tempted to discuss my analysis of why adult men become obsessed with anime and manga characters & similar ( not limited to Japanese men)

Computers can’t own real estate, silly.

Some would argue that computers now own all real estate.

Would that apply to grown men liking polymorphic sentient space rocks, too? :3

hmmm, I keep my phone in my pocket and am verified sterile.

The vasectomy may have had something to with that...

But can I blame the phone anyway?

Gee...I'm sure that my male friend who (with his wife) had horrible issues with infertility, would have been thrilled if it had been something as simple as a cell phone. Unfortunately, 30+ years ago, when they started trying to conceive, cell phones weren't that common. They finally did have a wonderful child, but the infertility cause was never determined. (In fact, they decided after child was born to throw away all contraceptives and never use them again, because they were a)willing to have more and b)logical enough to realize that if it was so hard in their 20s, it would probably be hard enough in their 30s that they could save a lot of money not paying for them. Child is still an only...

I think that I will concur with those up thread that this gives men something to blame their infertility on. We struggled horribly with infertility (though we began that struggle at about age 27 for me) and it had nothing to do with quality or quantity of husband's 'swimmers'. Nope we were female factor infertility all the way. As a matter of fact he was complimented often that even thought 8 years my senior and second and final child conceived at the age of 45 for him that his sperm quality was that of a man in his 20's. The rise of infertility in US society is multi-factorial. But the subset of women in fertility treatment are those who can afford it and so tend to be well educated and usually professionals. Since the vast amount of fertility treatment is out of pocket under most insurance plans in the US that is a very self-selected pool. Most who delayed child bearing intentionally and are now paying a price for that. Not that I am advocating women drop everything to have babies in their teens or twenties. As women have progressed toward an equal role in society, education (particularly college and graduate degrees) eat up a lot of the 20's, and the late 20's and 30's are spent embarking one's career. I also know a lot more women who are single until later in life, without as much push to marry in order to have a single male breadwinner, most are also delaying marriage. Meaning women in their 30's are just beginning to think about a child when their fertility is already on the decline. This is not all bad, these women are generally able to offer a degree of financial stability to a child, plus a degree of emotional stability as well. But the problem is if they are not very fertile they have a very short window to conceive a pregnancy. I think fertility care should be covered by more insurance and that people should have more access. So rambling now, but I do always recommend to any females that are thinking they might have issues to skip their routine OB/GYN and jump straight to a specialist. I probably would have had a lot less problems if I hadn't messed around with a series of regular practice OB/GYN and my flirtation with altmed before going to a fertility specialist.

It is such a common trend to blame an external cause rather than an internal one, I can't help but wonder if there is an actual name of the phenomenon.

Take the "vaccines cause autism"-crowd: in no way could it be genetics or age or anything else that could be "their fault". No, no, no - it is those damned vaccines that "destroyed" their originally perfect child.

If you smeeeeell.....what your phone......is cooking!) (sing as The Rock theme)

Take the “vaccines cause autism”-crowd: in no way could it be genetics or age or anything else that could be “their fault”. No, no, no – it is those damned vaccines that “destroyed” their originally perfect child.

Except that quite a few of these people I chatted with feel horribly guilty for having vaccinated their child. So it's more complex than than I think.

True enough on an individual level I suppose, but the general message/consensus of the anti-vaxx movement seems to be that parents and child alike are the victims of the ebul vaccines.

To me it seems that it appeals to a lot of parents because it takes the "responsibility" (if you could ever put the blame of genetic issues on the parent, which I wouldn't consider right in most circumstances) of the autism away from the parents and onto big pharma and vaccines.

"Mandrake, do you know why the commies put fluoride in the water ?" "So they can dilute it out 100-million times and cure everyone ?"

Dude...I trust the Telegraph and doctors far more than your flimsy advice. In case you haven't noticed, infertility in young men is on the rise. Maybe you should do some research and produce solid evidence for your claims, before penning another sad excuse for a "scientific article". Perhaps you should also consider studying actual science and biology, as well.
Are you some sort of expert on the human body? Have you spent years of your life hovering over textbooks and microscopes? What claim do you have to all this "knowledge" that you believe yourself to have?

Um, let's see. I'm a surgical oncologist, meaning I have an MD and have completed a general surgery residency and a surgical oncology fellowship, and I also have a PhD in a biomedical science (cellular physiology) and am quite well versed in cell biology and molecular biology. In addition, I've published in the peer-reviewed biomedical literature and successfully competed for peer-reviewed scientific funding.

so, yes, I've spent years of my life hovering over textbooks, microscopes, various scientific assays, peer-reviewed journals, etc.

Next question?

P.S. Speaking of surgical oncology, I will be a the Society for Surgical Oncology annual meeting in Boston from March 2-6, in case anyone wants to try for a meet up.

http://www.quickmeme.com/meme/3reuzq

Or maybe:

http://giphy.com/gifs/stephen-colbert-mic-drop-television-IOCXHPvn3WErm

@Orac: I will be a the Society for Surgical Oncology annual meeting in Boston from March 2-6, in case anyone wants to try for a meet up. Really wish I could. It's going to depend on how I'm doing for my statistics class, as to whether I can get up there or not.

Denice Walter, #7:
I know your comment is way down in the pile, but I have to point out that Bowie's young dudes were on the whole not particularly interested in, or likely to, impregnate anyone, both by choice of partner and of ofrifices of preference.

@ Old Rockin' Dave:

Oh I know. My gay university friends thought of it as an anthem: apparently so did Lou Reed.
Supposedly it had nothing to do with gay pride at all but the dudes were harbingers of the apocalypse or suchlike to come in five years.

Yabbut Orac Dude, are you any good at healing burns?

#79

Seriously? The Torygraph has a long history of being less than good with science and health reporting. Which is true of all the UK meejah, BTW.

And you must have tried really, really hard NOT to now who Orac is and what his background is, as that is just sooooo super-secret...

@ Denice Walker
Ever listen to Mott The Hoople's version?
I was at least on the fringes of that world. I wasn't, but I could have been, "you there with the glasses".

I presume you think that scientist at Technion Haifa and Carmel Medical Centre are cranks and you are sane. Read on:
February 3, 2016, 8:55 am
Men using a cellular phone for more than one hour a day double the risk of their sperm count dropping to levels too low for procreation, according researchers from the Haifa Technion and the Carmel Medical Center
A new study conducted at the two institutions, and published Tuesday in the medical journal Reproductive BioMedicine Online, brings evidence to support a long-feared link between dropping fertility rates in men and the prevalent use of cellular phones.

The quality of sperm among men in Western countries is constantly decreasing and is considered crucial in 40 percent of the cases in which couples have difficulty conceiving a child.

According to the findings, sperm counts dropped to levels that can cause infertility among men who kept their phones half a meter (c. 2 feet) or less from their groins. Forty-seven percent of those who kept their phone in their pants pockets throughout the day recorded abnormally low levels of semen concentration, compared to only 11% of the general male population.

Talking on a cellphone for over an hour a day or speaking on the device when it is being charged doubles the risk for low semen concentration, the study found.
“In light of the results of the study it is certainly recommended [that men] shorten the duration of calls and avoid carrying the device near their groins, sleeping next to it, speaking on it when it’s charging (it is in fact recommended to turn it off when it’s charging) and use headphones or a headset as much as possible,” Zilberlicht was quoted by Channel 2 as saying.

You clearly didn't bother to read my post, because it is exactly that study that I deconstructed in my post. Seriously, dude. Read the post. Then if you have specific criticisms based on its actual...oh, you know...contents, feel free to jump in!

I presume you think that scientist at Technion Haifa and Carmel Medical Centre are cranks and you are sane.

"Cranks" is such a harsh word. I would settle for "headline-whoring numpties".

The internet is a crazy place for nonsense.

(Cell Phones and Popcorn)

https://www.youtube.com/watch?v=pqIZDIxJgXw

What's the over/under on if Donchniak knows that the above video is fake, or not?

On one hand, the video has been widely debunked, and on the other hand, Donchniak is a loon. I can see it going either way.

Does keeping a cell phone in your pocket reduce male fertility?

gregladen — Sat, 14 Jun 2014 08:39:37 +0000

Does keeping a cell phone in your pocket reduce male fertility?

The tl;dr: maybe a little but for benign reasons. If fertility is important to you and you are a man, don’t put hot things in your pockets. This may fall into the category of switching from tidy whities to boxer briefs.

A study came out in September suggesting that it does. It is a meta-analysis by Jessica Adams et all, published in Environmental International, called “Effect of mobile telephones on sperm quality: A systematic review and meta-analysis.”

The study considered the effects of radio-frequency electromagnetic radiation (RF-EMR) on sperm motility (movement), viability, and concentration. As a meta-analysis, the study looked at several in vitro and in vivo analyses, combining the results, and using a statistical analysis to test the idea that RF-EMR has an effect on any one of these three variables. In total, ten studies were selected from a wider range of studies (the others were eliminated for various reasons) across which a total of 1492 sperm specimens were analyzed. The results, from the abstract:

Exposure to mobile phones was associated with reduced sperm motility (mean difference − 8.1% (95% CI − 13.1, − 3.2)) and viability (mean difference − 9.1% (95% CI − 18.4, 0.2)), but the effects on concentration were more equivocal. The results were consistent across experimental in vitro and observational in vivo studies. We conclude that pooled results from in vitro and in vivo studies suggest that mobile phone exposure negatively affects sperm quality. Further study is required to determine the full clinical implications for both sub-fertile men and the general population.

Not all studies looked at all effects and there were other differences between them. See the original study (link above) to find all the details.

Of the nine studies that looked at motility, six indicated a reduction due to mobile phones. Five of the studies looked at viability, with four of the five indicating a negative effect. Six studies addressed concentration but with very inconsistent results.

An effect means little unless there is an explanation that makes sense. Several different ways in which RF-EMR could affect sperm are considered in this meta-analysis.

One possible cause is production of reactive oxygen species (ROS) which could lead to DNA damage. ROS are molecules including Oxygen that happen in the normal day to day course of biological activity in cells but that can increase in frequency for a number of reasons, including, and most famously, ionizing radiation. Oxygen is a highly reactive element. When life first arose on earth, Oxygen was not commonly available and was generally destructive to the finely tuned molecular processes associated with living form (probably, and I oversimplify). But life processes tended to release oxygen from molecules in which it was more or less safely sequestered. By and by life processes evolved that handled oxygen by re-sequestering it, life processes evolved that made use of the highly reactive nature of oxygen.

An analogy for this is Xander Cage (Vin Diesel) in the movie xXx. Cage is a dangerous out of control tough guy who has capabilities that the government (represented by Agent Augustus Eugene Gibbons, played by Samuel Jackson) requires for an important task. Cage is tamed, in a sense, so he can carry out the government’s bidding, but at the same time he remains dangerous. There are many movies with this theme. Imprisoned highly capable and dangerous bad guys are given a chance to play a useful role; they are needed because of there capabilities, but their capabilities are dangerous ones, so their exploitation comes with a risk. The exploitation of one of nature’s most dangerous elements, oxygen, provides life with some incredible capabilities, but as a risk.

Oxygen is usefully employed by nature. Oxygen damages biological processes. Nature employs counter measures to minimize that danger (i.e., “anti-oxidants”). But sometimes those counter measures are not enough, either because a very rare form of ROS comes along, one that is not accounted for by life’s counter-measures, or because a counter-measure is simply overwhelmed (or otherwise interfered with).

So in this scenario, RF-EMF cause the generation of a greater quantity of ROS, or especially damaging ROS. My understanding is that this is generally considered unlikely because the range of RF-EMF produced by cell phones is thought to not be physically capable of influencing ROS quality or quantity. However, the authors of this study argue that it is possible:

A small amount of ROS has an important functional role in sperm capacitation, the acrosome reaction, and binding to the oocyte (Garrido et al., 2004). Experimental disruption of the flow of electrons through the mitochondrial electron transport chain has been shown to increase ROS production significantly, with negative consequences for sperm motility (Koppers et al., 2008). In vitro evidence found EMR emitted at the same frequency as mobile phones increased mitochondrial ROS production and DNA fragmentation in sperm, and decreased motility and viability ( De Iuliis et al., 2009). The trends seen in this meta-analysis are consistent with these effects.

A second kind of effect is thermal. Sperm normally develop, in humans (and perhaps mammals in general) in a narrow range of temperatures. Increasing temperatures could interfere with this. There are two ways in which temperature increases could occur. One is that the RF-EMF excites molecules at the site of spermatogenesis, increasing temperatures. RF-EMF in the range emitted by cell phones can certainly do this if there is enough energy. This is what a micro-wave oven is. This particular thermal effect is minimal with cell phones. Were it not minimal we would be slowly cooking our hands and faces while we talked on the phone. Still, at least one study cited by Adams et all shows an increase in heat of people’s faces while they are taking on a cell phone. It is possible that a very small effect that normally has no biological significance would affect sperm production because it is sensitive to heat changes. This effect is considered to be very unlikely as it is simply too small.

However, cell phones also become warm, and this heat could be transmitted to the site of spermatogenesis. I learned about hot cell phones shortly after getting my first smart phone. I had left some apps running (I think the camera app was the culprit) and blanked the screen. The phone sat in my pocket for a while and I noticed a very uncomfortable sensation of increased heat. When I took the phone out of my pocket it was quite hot. It is possible that this made my sperm unhappy.

This study has some severe limitations, some of which are discussed by the authros.

Heterogeneity, that is variation between studies that is greater than expected due to sampling error … is an issue in most meta-analyses. Heterogeneity was high in all our meta-analyses (I2 > 88%) … However, our meta-analysis did include nearly 1500 samples, which increases confidence in the results. The heterogeneity in the motility meta-analysis was partially due to the differences in mobile phone exposure times, as the subgroup analyses demonstrated. The high heterogeneity and relatively low number of studies also precluded meaningful assessment of publication bias… However, sensitivity analyses demonstrated minimal differences when individual studies were excluded, with a tendency for our results to be conservative.

The possibility of confounding variables influencing the results of the observational studies cannot be ruled out. For example, participant age and smoking status were not consistently reported, so it is possible that these affected the observational studies since they are known to affect some semen quality parameters … [S]tudy populations taken from fertility clinics, as used in many studies on male fertility, may not be representative of the general population, as they are likely to contain a higher proportion of men with sperm parameters outside the WHO reference range.

Again, see the original study for more detailed discussion of these limitations.

It is possible that studies that fail to show an effect are simply unpublished and if available would balance out the meta-analysis. The degree of effect is small, so if there was random variation in outcome and several studies on one side of the mean outcome are removed, a small effect would be expected. There may be something about men who keep their cell phones in their pockets that relates to infertility. That seems like a strange idea, but if, for example, thermal effects are important, simply keeping numerous objects in one’s pockets could affect air flow and heat distribution in and near the nether regions. There is no control here; there is not a study of men who keep objects that are identical to cell phones but electronically inert (placebo-phones, if you will) in their pockets. Perhaps men who keep their cell phones on belt clips represent the higher-sperm production men while those who keep their cell phones hidden away have lower sperm production. A control study that looks at external cell phone attachment devices, and probably pocket protectors and other paraphernalia, in relation to fertility and overall manliness would be … well, probably not fundable so forget it.

The important outcome of this study, I think, is that a careful look via many studies of the effects of cell phones on a biological process known to be rather delicate (the making of sperm) shows only a minor effect at best, with much equivocation on whether there is an effect at all. Furthermore, the most likely effect is simply heat, having an object in your pocket that generates extra heat in a region where evolution had previously designed a cooling mechanism, a dangling scrotum that normally keeps the external testes away from the body.

There is the possibility that if anything is happening here at all, it would effect sperm quality in other ways, including DNA or chromosomal damage. That would be important to know. Female egg production is very different from male sperm production, so the two cases are not very analogous, but if there is an effect on sperm it might be worth asking if there is an effect on age. If the effect is anything other than heat, i.e., if it has to do with RF-EMR affecting molecules in cells, then something very important may be going on other than a small effect on fertility. Affecting molecular activity with radio waves might be a thing, and an area of future research and the possible development of medical diagnosis or even treatment. Most of the claims of radio waves for therapy or treatment, however, are wooish bunk. It seems that more study is merited, but for interesting academic reasons and not because this is a clear and present danger.

gregladen Sat, 06/14/2014 - 04:39

Tags

Olfactory-like signaling in mammalian sperm

cagapakis — Sun, 26 Sep 2010 19:54:49 +0000

Olfactory-like signaling in mammalian sperm

So I was browsing the internet for info on G-protein coupled receptors and ended up finding some interesting facts about sperm. It turns out sperm don't just swim blindly, hoping to randomly bump into eggs. Instead, like bacteria, sperm can sense their chemical environment and adjust their swimming accordingly. Sperm have a sense of smell.

The (g-protein coupled) olfactory receptors in our noses that activate our sense of smell were discovered in 1991, an amazing discovery that earned the 2004 Nobel prize for physiology or medicine. The receptors sit on the surface of the cells up high in our nose, and smelly chemicals in the air we breath bounce around on them. When a molecule bounces onto the specialized receptor that recognizes it, the receptor turns on and activates the G-protein coupled to it, in this case G-olf. G-olf then goes on to activate a cascade of other proteins which end up opening protein channels in the cell's membrane, allowing ions to flow through. The ion flow changes the electrical potential of the cell and starts the electrical signal that will make it all the way to the brain--that is if the receptor is in your nose.

After the initial discovery in the nose, olfactory receptors kept showing up in all sorts of tissues--in the heart, in the spleen, in the prostate, and even in sperm. On the sperm cell, what the receptors are doing is a lot harder to figure out than in the nose, especially in a way that is meaningful to how sperm swim in their natural environment. In vitro studies of sperm in a test tube identified chemicals that can activate the sperm olfactory receptors and others that will block them, but the model of how the receptors are connected to the waves of calcium ions that control the swimming motion of sperm is full of question marks. Even the chemical that sperm swim towards in vitro has no apparent physiological significance, bourgeonal being a chemical common in perfumery for its lily of the valley scent. Understanding the biochemistry of the sperm olfactory receptors in their physiological context may some day have impacts in fertility treatments, in vitro fertilization technology, and perhaps even hormone-free contraceptives, although the authors of the review that introduced me to world of sperm olfaction cautiously note that:

such speculation may still be a long way from future drug development and subsequent clinical trials. It will be challenging to demonstrate efficiency and inoffensiveness of potential pharmaca as well as to discover suitable ways of drug application.

Olfactory receptors turning up in unexpected places can expand our understanding of the way that cells interact with their environment, whether it's how we navigate our smellscape or how sperm navigate to the egg. Findings like these also highlight the generalness of many of the proteins involved in cellular signaling and the flexibility of the olfactory receptors themselves--their general usefulness in sensing chemicals for all kinds of cells and the evolutionary conservation that allows even yeast to be engineered to have a sense of smell. So three cheers for olfaction and three cheers for all the G-protein coupled receptors!

cagapakis Sun, 09/26/2010 - 15:54

Tags

one immediate application: lily-of-the-valley-scented birth control!

er, prophylactics.

thanks for the heads-up on this research! very cool stuff!

Fascinating research, but I really wonder why any woman would want birth control that *doesn't* switch off your periods - ill for a week or more each month, versus slightly reduced life expectancy. Not a difficult call.

If you went back far enough in evolutionary time, to our parent fishes and then far, far beyond, would human evolutionary history coincide with that of human gametes?

In other words, is it evolutionarily reasonable to say that we are eggs and sperm writ multicellular? Or, at least, that our earliest multicellular ancestors were? Or is that unresolved because the origin of sexual reproduction is unresolved?

In other other wordsâ¦ do sperm sensory features likely date back to the period when our ancestors were multicellular, or do they likely come afterwards, as an innovation specifically in the environment of navigating the body of the female? Or is it in-between, dating from the phase where, like modern fish, our reproduction didn't involve connective mating?

In any case, sperm sensation is apparently useful today, whether that's due to aiding the sperm's "host human" or (much more likely) out-competing the human's other sperm.

This is also the same way leukocytes (including neutrophils, macrophages and lymphocytes) migrate to sites of inflammation. Cells at inflammation sites release chemokines that interact with the GPCR of leukocytes and modify their cytoskeleton - making them move up the chemokine concentration gradient, towards the source of inflammation.
GPCRs are pretty badass! :)

G-Spot.

"So I was browsing the internet for info on G-protein coupled receptors"

I used to do that all the time; it's hard for single G-proteins to find an acceptable partner in the hustle and bustle of modern life, but then I found
www.sikapaga.com

Sure, there's a survey to fill out, and a fee to pay, but judging by the gushing testimonials, a lot of lonely G-proteins have found their ideal life partner this way....

G-protein coupled receptors and ended up finding some interesting facts about sperm. I loved all of these posts. A lot of these things we have, but I got some really great ideas.

Sperm war - the sperm of ants and bees do battle inside the queens

edyong — Thu, 18 Mar 2010 13:00:28 +0000

Sperm war - the sperm of ants and bees do battle inside the queens

One night of passion and you're filled with a lifetime full of sperm with no need to ever mate again. As sex lives go, it doesn't sound very appealing, but it's what many ants, bees, wasps and termites experience. The queens of these social insects mate in a single "nuptial flight" that lasts for a few hours or days. They store the sperm from their suitors and use it to slowly fertilise their eggs over the rest of their lives. Males have this one and only shot at joining the Mile High Club and they compete fiercely for their chance to inseminate the queen. But even for the victors, the war isn't over. Inside the queen's body, their sperm continue the battle.

If the queen mates with several males during her maiden flight, the sperm of each individual find themselves swimming among competitors, and that can't be tolerated. Susanne den Boer from the University of Copenhagen has found that these insects have evolved seminal fluids that can incapacitate the sperm of rivals while leaving their own guys unharmed. And in some species, like leafcutter ants, the queen steps into the fray herself, secreting chemicals that pacify the warring sperm and ease their competition.

The amazing thing about this chemical warfare is that it has evolved independently several times. Social insects evolved from ancestors that observed strictly monogamous relationships. Even now, the queens from many species mate with just one male during their entire lives. With just one set of sperm in their bodies, they have no problem with sperm conflict. The trouble starts when species start mating with several males during their nuptial flights, as honeybees, social wasps, leafcutter ants, army ants, and others do today.

To understand the sperm wars, den Boer exposed sperm from different species to their own seminal fluids, those of brothers, or those of unrelated males. In two species of bees and three species of ants, she found that a male's seminal secretions are a boon to his own sperm. Even at small concentrations, they managed to boost the survival of sperm that had been stored in saline.

In species where queens mate with a single male, like bumblebees and Trachymyrmex zeteki ants, the seminal fluids had the same beneficial effect on the sperm of unrelated individuals. But these chemicals weren't so benign in species where queens store sperm from several males, like honeybees and the ants Atta coloimbica and Acromyrmex echinatior. There, they significantly reduced the survival rates of competitor sperm, slashing them from 6-18% after just 30 minutes.

How seminal fluids know to attack other sperm is a mystery. The fact that a brother's sperm also suffers, even though it shares much of the same DNA, suggests that the method involves a blanket attack on anything that isn't recognised as "self". And as with many wars, both sides suffer. It turns out that the protective chemicals from one set of seminal fluids can't counteract the destructive chemicals from another. If the two are mixed, no set of sperm survives very well.

From the queen's point of view, these battles are positively counter-productive. The more sperm she has, the more eggs she can fertilise and the more young she can raise. It's in her interest to stop the sperm from killing each other. Den Boer found that the queens of the leafcutter Atta colombica do just that. The fluids from a queen's spermathecae (the organ where she keeps her sperm supplies) can quell the destructive effect of rival seminal fluids. If they're added to the mix, survival rates for all the stored sperm shoot back up to normal levels. If the sperm wars get too heated, the queen evolves to restores peace for the sake of her future kingdom.

Reference: Science http://dx.doi.org/10.1126/science.1184709 If this link isn't working, read why here

Images: all photos by Susanne den Boer

More on sperm competition:

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edyong Thu, 03/18/2010 - 09:00

This article is A.W.E.S.O.M.E.

One night of passion and you're filled with a lifetime full of sperm with no need to ever mate again. As sex lives go, it doesn't sound very appealing, but it's what many ants, bees, wasps and termites experience.

Not termites. Termites have a king who continues to mate with the queen over the course of their lives.

Hi Ed,

I found your blog online. I just wanted to say that I am really happy to see that you thought our paper was nice enough to write a piece about. You are clearly a talented writer, I think the way you wrote about our research is perfect, you got all the facts right and it is written in a very clear way.

It's awesome, thanks so much!
Best Wishes, Susanne den Boer

'... the queen evolves to restores peace for the sake of her future kingdom.'

Should be 'queendom' don't you think?

Fascinating, like all of your posts. You do a great job here!

There is a neat paper on sperm competition in Drosophila published on-line in this week's ScienceExpress.

Trout with salmon parents could help to revive endangered fish species

edyong — Fri, 28 Aug 2009 08:00:31 +0000

Trout with salmon parents could help to revive endangered fish species

This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science.

Getting excited when fish produce sperm would usually get you strange looks. But for Tomoyuki Okutsu and colleagues at the Tokyo University of Marine Science and Technology, it's all part of a day's work. They are trying to use one species of fish as surrogate parents for another, a technique that could help to preserve species that are headed for extinction.

Okutsu works on salmonids, a group of fish that includes salmon and trout. Many members of this tasty clan have suffered greatly from over-fishing in the last few decades, and their populations are dwindling their way to extinction.

If stocks fall below a critical level, they may need a jump-start. One strategy is to freeze some eggs to be fertilised artificially, in the way that many human eggs are in fertility clinics. But it's much harder for fish eggs - they are large and have lots of fat, which makes them difficult to freeze effectively.

Okutsu's group have hit on a more effective solution. They use transplanted sexual stem cells to turn another species of fish into surrogate parents for the endangered ones.

The technique revolves around special cells called spermatogonia. In humans, these eventually become sperm. But in an earlier study, Okutsu found that the spermatogonia of fish are like sex stem cells, with the ability to become either sperm or eggs. When transplanted into a host species, they should develop into both types of sex cell.

But that wasn't to be. The transplanted cells only produced a very small number of donor sperm cells, which would have needed to be sorted from the host's far greater supply of its own sperm. The transplanted cells also never produced viable eggs, putting the kibosh on any breeding attempts.

Undeterred, Okutsu's group found a solution for this too and it was a remarkably simple one. They used sterile hosts that couldn't produce their own sex cells - if they made any, it must have been because the transplants had taken.

As hosts, they chose masu salmon that suffered from a condition called triploidy. Rather than pairs of chromosomes, their cells carried triplets, and the extra set rendered them infertile.

Okutsu took spermatogonia from rainbow trout and implanted them in the newly hatched salmon. Normally, the male triploid salmon never develop proper testes and the females never produce viable eggs. But not so for the transplant recipients - most of them developed normal sets of both sex organs and sex cells.

Ten of the 29 males produced milt, the fish equivalent of seminal fluid and five of the 50 females released mature eggs.The group used sperm from the surrogate males to fertilise eggs from the surrogate females and to their relief, the resulting embryos did very well. The vast majority hatched and developed normally.

When he checked the DNA fingerprints of this new generation, he saw that they were all 100% trout. Even their mitochondria were trout mitrochondria. The team had successfully bred baby trout from surrogate salmon parents. The newborns even grew up to become fertile adults, capable of producing young trout of their own.

Best of all, the team found that 45% of frozen spermatogonia survive the thawing process intact. That means that their technique is not only feasible but practical. Even if rainbow trout went extinct, Okutsu could breed new ones if he had enough of these cells in cold storage.

Update: This piece has been kindly reposted on the Reef Tank. Check them out for more marine morsels.

Reference: Okutsu, Shikina, Kanno, Takeuchi & Yoshizaki. 2007. Production of trout offspring from triploid salmon parents. Science 317: 1517.

edyong Fri, 08/28/2009 - 04:00

Tags

Surrogate parents of both sexes... sometimes science gets weirder than science fiction.

Some years ago, a colleague was working on salmon genetics. He showed me viable salmon eggs and spern he had collected some months before. I don't think he was freezing the eggs. I'll see if I can find the reference to the paper he published.

I think the reference is Aspinwall, 1974, but I can't easily find a copy on line. He had access to a cold-water spring and was raising batches of little salmon in wooden tanks with a flow through system.

Super interesting post. The only thing I'd note is that rainbow trout aren't likely to go extinct any time soon - they are one of the most ubiquitous and successful freshwater fish species on the planet. In fact their introduction and/or invasion into streams where they were not formerly found can spell trouble for local endemic species, with whom they compete, and sometimes interbreed (e.g, West Slope Cutthroat in the US). Many other salmonids, however, are in trouble, and this technique might help to restore their populations. They'll have to show that it works for those other species, too, though.

Thanks for the write-up. I work with testicular germ cell tumors in zebrafish, so this stuff is my bread and butter.

The Evolution of Ejaculation Strategies

jchosy — Tue, 14 Jul 2009 10:12:16 +0000

The Evolution of Ejaculation Strategies

According to a paper to be released in the September issue of the journal "American Naturalist", the number of sperm a male ejaculates may be correlated to his attractiveness as measured by the females in the population. The idea came forth after scientists at University College London and the Oxford University mathematically modeled the optimal "sperm load" to maximize daddiness across a range of mating patterns. The research, which took place late one Friday night at the corner bar, was one of several proposed ideas to "settle a bet" between two of the scientists.

The results suggest that males who attract more females may produce fewer sperm per mating than those who aren't so lucky. Essentially, the model shows that the optimal way to get lots of offspring is to mate with as many females as possible, even if those matings involve fewer sperm and, thus, a lower probability of conception per 'bow chicka bow wow'. Conversely, males with fewer opportunities to mate should put all their sperm in whatever baskets they can woo. This increases the probability of conception per mating, an advantage when you can't get much.

This idea is in contrast to the assumption that higher quality males are more fertile. The authors recognize that the pattern may not hold true for all species, given the diversity of mating strategies across taxa. They also state that it is difficult to know how these findings apply to humans and other primates. However, we all know that was just a CYA statement and, in actuality, they nailed it.

Future studies will focus on comparing sperm load in males that are similarly attractive but with differing access to prime sperm-making resources. The authors do not mention which species will have the joy of settling this bet, but the odds of the results being apt for Homo sapiens are about 100:1.

Fig. 1 A schematic representation of optimal sperm load by relative attractiveness

Mr. Sprinkles

Exxon Valdez

Citation:
'The evolution of continuous variation in ejaculate expenditure strategy' by S. Tazzyman, T. Pizzari, R. Seymour, and A. Pomiankowski will be published in the September issue of the journal American Naturalist.

jchosy Tue, 07/14/2009 - 06:12

Tags

survival of the spunkiest

It post-ejaculation strategies that are the real problem.

Unless you don't give your real name.

Hahahahahah, I'm glad you guys are back. You crack me up.

Bizarrely, that actually makes a lot of sense.

There are a number of fish species which have "sneaky males" in addition to regular males. The sneaky males look and act like females or juveniles. They generally join in on regular spawning activities. I recall one instance where the sneaky males were called "super males" because their testes where several times as large as the testes of regular males.

I'd be interested to know if perceived attractiveness also correlates with testes size. If less attractive males tend to produce larger loads per coupling, they may also have larger testes, on average, to support these larger loads.

Also, I love science articles that discuss things like ejaculation strategies.

Great first post. Informative and funny. I'll make a regular stop here...

you might want to check out this classic conversation starter:
Soler, C., Nunez, M., Gutierrez, R., Nunez, J., Medina, P., Sancho, M., et al. (2003). Facial attractiveness in men provides cues to semen quality. Evolution and Human Behavior, 24, 199â207.

Two studies show that rated attractiveness positively correlates with sperm morphology, motility and some kind of "sperm index", but interestingly, NOT with concentration.

Lol to the males putting all their sperm in whatever baskets they can woo.

I think they did the study with chickens, right? It all sounded a bit suss to me...

..,there are lots of option about the medications of pre ejacuation among men... with so many option how can i be able to know which one is suited for me??????

Friday Flash Fun: Spermrider

sciencepunk — Fri, 12 Jun 2009 08:12:10 +0000

Friday Flash Fun: Spermrider

Remember all the fun you had with the Great Sperm Race game a while back? Well, now you can step it up a level with Sperm Rider. In this game you play a delighted little guy in a cowboy hat, riding on a giant spermatozoa through a city drawn crudely in crayons. Using your "seed of destruction", set about squishing the local populace, and fend off attacks from tanks, helicopters and jet planes by deflecting their missiles with your long tail. It's all set to brilliant music and has very little to do with any kind of science, but I like it anyway. Just make sure you don't "ruin everything" by dying.

sciencepunk Fri, 06/12/2009 - 04:12

Tags

games

sperm

games

Friday Flash Fun: The Great Sperm Race

sciencepunk — Thu, 30 Apr 2009 22:13:34 +0000

Friday Flash Fun: The Great Sperm Race

Sex is fun, but it's nothing compared to the thrilling life-or-death struggle spawned by passionate, unprotected lovemaking. Thankfully, to promote Channel 4's The Great Sperm Race, Flash game maestro Johnny Two Shoes has conceived a game that puts you in the cockpit of a humble gamete struggling to become whole again.

Like a super-fecund cage match, 250 million enter, but only one leaves. Can you safely navigate the acid-filled folds of the vagina and outwit the hungry leukocytes to bury yourself into the egg in an explosion of zygotic glory? Find out now!

sciencepunk Thu, 04/30/2009 - 18:13

Tags

best game ever

Are your sperm short-lived and tiny?

sporte — Sat, 27 Sep 2008 13:16:00 +0000

Are your sperm short-lived and tiny?

Then you need to head over to The Oyster's Garter and read Miriam Goldstein's incredibly funny post about the problems of male sea squirts.

Apparently, if you're a sea squirt, the size of your sperm is related to your environment and mostly the number of other sea squirts in your environment.

Usually, I'm not attuned to the issues of broadcasting spawn or the lives of those who live under a dock, but Ms. Goldstein channels Dr. Tatiana so well, I found myself sympathizing and laughing out loud at the struggles of the tunicates.

Sometimes extremely handsome pleats just aren't enough.

sporte Sat, 09/27/2008 - 09:16

Tags

Biology (Macroscopic )

So glad you enjoyed! Truly, it's not the size of your sperm, it's their motion in the ocean.