Pharyngula

The effect of porn on male fertility

Once again, I bravely plunge into the fascinating world of kinky sex research in humans. This time, we learn something incredibly useful. Gentleman, would you like to know how to improve the potency of your semen? Do you need a good excuse to give your significant other when she catches you browsing porn sites? Do you want another excuse to sneer at those pompous business types who flaunt their fancy cell phones? Here’s the study for you.

There’s a vested interest in bettering male sperm quality at fertility clinics, obviously. There are multiple ways to measure the potency of a semen sample: one is to look at sperm density, which is typically in the neighborhood of 70 million sperm per millileter. Another is to look at sperm quality, measured as the percentage of functional, motile sperm in a sample. These are routine assessments that the professionals at fertility clinics make on a regular basis, and are easily quantified.

Now for a little theory: if males can regulate their sperm quality (as we’ll see, we apparently can), then the situations in which we ought to be putting a little extra oomph into the boys is when there is a possibility of competition: if we’re concerned that someone else might be introducing sperm into our favorite vagina, we ought to make a special effort to put our best wigglers in the race.

How can this be tested? With the judicious use of pornography. A group of young heterosexual men were asked to masturbate into a cup, while provided with a randomly selected set of graphic images for stimulation. The set to elicit feelings of sexual competition consisted of explicit images of two men with a woman; the less competitive images were of three women. The fellows filled out a little questionnaire that asked miscellaneous details, were handed a cup and some calipers (they also had to measure the size of their testes) and a sealed packet with their porn, and returned a little later with their output.

The results fit the hypothesis. Males who viewed the hardcore shots of other men with a woman produced more sperm (76.64±1.26 x 106/ml vs. 61.35±1.27 x 106/ml), and a higher percentage (52.1±7.3% vs. 49.3±8.0%) were actively motile. The men who thought the photos were more explicit than any they had seen before also had more potent semen than those who thought the images were relatively tame—the effect of novelty was strong.

A few other interesting correlations emerged. Moderate coffee drinking increased the sperm count. On the other hand, men who a carried a mobile phone in a hip pocket or on their belt (but not if they carried it elsewhere) had reduced sperm counts: 65.6±1.26 x 106/ml vs. 75.67±1.30 x 106/ml.

All of these results were statistically significant.

We can learn some important lessons from this.

  • Ditch the cell phone!
  • Drink coffee—it makes you more manly.
  • Don’t look at porn too often, since you can habituate.
  • When you do look at porn, the more explicit, the better.
  • Here’s the awkward one: the more studly guys lounging about in your porn, the more anxious your gonads will be, and the better their production.

Now when your girlfriend or wife finds you at the computer, coffee cup in hand, browsing some hardcore porn site, you can tell her that you are just trying to enhance your virility…and you have the statistics to support it. Of course, she’s also going to be able to tell you to stop obsessively scanning through the two hundred porn portals you’ve got bookmarked—all things in moderation.


Kilgallon SJ, Simmons LW (2005) Image content influences men’s semen quality. Biol. Lett. 1:253-255.