Genetic Future

Note: I’m splitting this off from my earlier post on 23andMe’s encouragement of genetic testing of children, since I think this rather speculative argument distracts from the main point of that post.

I mentioned in my previous post that there’s a real danger that parents might try to use information from current genetic tests to steer their children in specific directions (and that at least one company is already touting such a test) – but the information available right now from genome scans simply isn’t accurate enough to justify such decisions.

For instance, to mention a field close to my own heart, the genes currently known to affect athletic performance likely explain less than 5% of the variation in traits such as muscle strength and cardiorespiratory fitness. Any parent seeking to decide which sport their child would be best suited to would be far better off simply encouraging them to try a whole variety of activities and seeing which ones they were best at (and which ones they enjoyed the most); the addition of currently available genetic data would have marginal benefit, if any.

The same applies to an even greater extent when it comes to traits affecting career decisions – intelligence, personality, even attractiveness. Some of these traits are strongly influenced by genetics, but the actual genetic variants affecting them are currently almost completely unknown, and you should be extremely wary of anyone who tells you otherwise (e.g. these guys).

However, it won’t be long before many of the genes underlying many traits relevant to career choices and life success are known, after which the equation is forever changed. Although in the vast majority of cases genetic predictions will still be probabilistic rather than deterministic (since there are many non-genetic factors that affect these traits) it would seem rational to gently steer children towards life paths that are most likely to maximise their overall potential, as determined by both genetic and non-genetic tests.

A society where people make decisions about their children based on genotypes needn’t resemble the dismal fatalism of Gattaca. With further education the public will hopefully begin to move away from the deterministic “gene for x” mentality that currently dominates, and towards a more subtle and probabilistic model of genetic predisposition. In addition, it’s important to remember that as genetic technology advances so will the rest of medicine, so that by the time we have the ability to predict genetic disease risk we will likely also have the ability to intervene and correct major diseases well before the first symptoms arise.

But even in those situations where medical correction is unavailable (or, more likely, unaffordable), so long as genetic data are used as a guide rather than a sharp constraint on future career options this technology will generally have positive rather than sinister implications for society.

To further the athletic example above: rather than using genetic information to block children from becoming athletes altogether, coaches and talent scouts might use it to guide promising young athletes into the sports to which they are best suited. The same model could apply to any other arena. So long as it can be shown that genetic predictions are both accurate and relevant, I find it hard to see how it could be unethical to use them to help kids make choices about their futures; the kids themselves will still be the only ones who can determine whether or not they will succeed. Naturally, careful industry regulation will be required to ensure that this model – rather than some naively deterministic algorithm – is the future of gene-based career counselling.

Please note that I don’t believe that genetic testing will ever be used as the be-all and end-all of career guidance, but rather as a tool for career counsellors and other professionals (e.g. athletics coaches) to add to their existing battery of tests. It will likely turn out that for many traits the genetic data is already effectively captured by simply assaying direct or indirect measures of the trait itself, making genetic tests completely redundant in such cases. However for other traits – particularly where there is a need to make early predictions before the trait itself is evident – genetic tests may provide a useful tool.

This is all pretty speculative right now, but these are issues that society will have to wrestle with very soon, probably much sooner than we are really ready for them. It’s obvious that DNA-based trait prediction tests will be popular with many parents, as evidenced by the fact that companies are already offering them despite the laughably poor predictive power of currently known genes. The sooner we start having a constructive and realistic discussion about the best way to use these tests, the better.


  1. #1 Daniel MacArthur
    October 31, 2008

    Steve said in the previous comment thread:

    Awww come on now… you actually mean to think you can state that and get away with it. Here’s what you said

    “2. I can’t see why having extra (reliable) information to inform your decisions necessarily makes life dull. Do you inform your patients not to have their cholesterol tested because it would take all the mystery and romance out of their future?”

    Is cholesterol really the same as the 9p21? Well, no….it (cholesterol) has been studied for over 30 years now….unlike your fancy SNP garbage from 2007….which BTW failed replication in a dutch population….

    Bad info is far worse than no info at all buddy……

    I made it pretty clear in my post that I don’t believe current genetic data are sufficient to make such decisions, so you’re arguing against a strawman.

    The issue here is the use of genetic tests that have been extensively replicated and validated – and we both know (given the extensive heritability of many interesting traits) that such tests will eventually exist for all number of things. If a genetic test is just as predictive as a cholesterol test there’s no question you’d use it in a clinical setting. Why not use it to help kids decide what they want to do with their lives?

    Again, I’m only talking about information that has been unambiguously demonstrated to be accurate and relevant. Such tests don’t exist today for most traits – but they may well do eventually. When they do, will you be arguing that parents shouldn’t be allowed to use them?

  2. #2 Steven Murphy M.D.
    October 31, 2008

    I understand. But by putting this out there, companies are encouraged to promo non valid tests to do the same thing!
    Even reporters at the WSJ are getting in on it. We have to make sure that the public understands the limitations PRIOR to doing the testing! Not after we collect payment!!

    Gene Screen: Will We Vote Against a Candidate’s DNA?



  3. #3 N/A
    October 31, 2008

    Even if we have the ability to test your genetic makeup for a possible career, we still should not do it. Just because we can do it does not mean we should do it. There are some aspects of life that we just need to keep sacred…like trying to overcome odds.

    I’m not even close to a smart person myself. If I were to gave a genetic test done that showed I was stupid, I would just throw it in the trash and prove the testers wrong.

  4. #4 tony
    November 1, 2008

    As a self certified “alpha”, I think it’s great to start genetic testing now. When we alphas finally perfect artificial wombs, we can dispense with surplus betas once and for all. Excuse me, I’m off to do some Soma.

  5. #5 Comrade PhysioProf
    November 2, 2008

    Dude, why are you censoring comments that are critical of your conclusions? That’s pretty wack-ass behavior for a scienceblogger.

  6. #6 Daniel MacArthur
    November 2, 2008

    Dude, make a substantive comment that doesn’t include the words “horseshit” and “wackaloon” and I’d be more than happy to engage.

    I do my best to keep the comment threads civil; you don’t get a free pass just because you’re a Scibling. But you have reminded me that I need to set up a proper comments policy to make this clear.

  7. #7 Comrade PhysioProf
    November 2, 2008

    HAHAHAHAH!!! The LANGUAGE POLICE!!! OK, how’s this, dude?

    The idea that any time soon–if ever–there will be genetic tests predictive of the complex human character traits and cognitive capacities that are relevant for predicting success in particular careers is completely absurd. This is because these traits and capacities arise out of horrendously complex interactions between large numbers of genes and environmental factors, and we have essentially no idea whatsoever what these interactions are, let alone how they occur.

    And, BTW, I can see how you might rationally have some priggish objection to words traditionally considered “foul language”, but what’s your problem with “wackaloon”!? HAHAHAHAH!!!!

  8. #8 Daniel MacArthur
    November 2, 2008

    Yeah, that’s much better. It’s not about swearing, btw – it’s just that any discussion where one side starts off by dismissing the other’s arguments as “wackaloon” is unlikely to prove constructive (at least in my experience). Also, rude bastards like you have an unfair edge when it comes to insult-slinging competitions. 🙂

    Anyway: you’re just guessing when you say that “these traits and capacities arise out of horrendously complex interactions between large numbers of genes and environmental factors” – the genetic architecture of these traits simply hasn’t been characterised.

    We do know that many human behavioural traits are surprisingly heritable (shockingly so, in at least some cases) – it’s true that we have no idea precisely which genes influence these traits, but that’s a situation that’s unlikely to last forever.

    I admit it’s likely that most of these strongly genetic traits will be influenced by many small-effect genetic variants, making gene-based predictions extremely difficult. Still, I wouldn’t rule out the possibility of some moderate-effect variants explaining a significant fraction of the variance for some important traits; and even the most horrendously complex traits will eventually give up most of their secrets, given sufficiently large population studies. Of course, you might be right that gene-gene and gene-environment interactions will overwhelm any predictive signal for many of these variants, but that’s far from a certainty (there isn’t much evidence for widespread gene-gene interactions from most recent genetic analyses of complex traits, although their power to detect this has admittedly been pretty low).

    Again, I’m not arguing for a situation where some mad-eyed geneticist feeds your genome sequence into a machine that spits out your optimal career. Rather, I’m arguing that genetic tests may ultimately offer probabilistic information about a kid’s eventual predispositions and aptitudes, and that such information may – in some cases – prove to be a useful addition to the existing aptitude tests used by career guidance counsellors.

    There’s every chance I’m wrong – but I don’t think anyone knows enough right now to say that I am with any certainty. As such, it seems reasonable to start weighing up the ethical issues now rather than simply dismissing the possibility out of hand as “absurd”.

  9. #9 Comrade PhysioProf
    November 2, 2008

    Comrade PhysioProf is not a “rude bastard”. He is a kind, gentle, and loving soul.

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