Designer Babies Revisited – Response to Nita Farahany

Co-blogger Nita Farahany takes issue with “many parts” of my post defending the morality of designer babies against claims that they would lead to unjust inequality. I always welcome a good debate. But, in this case, virtually all of the things she “takes issue” with are not actually things I said in my post.

First, and most obviously, I did not “seeming[ly]…endorse… state control of reproduction.” To the contrary, the whole point of my post was to argue against people who do favor such control on the grounds that restriction of designer babies is needed to prevent inequality. In my judgment the state should not force parents to genetically enhance their offspring, but it should also not ban them from doing so, except perhaps in cases where the technology is dangerous or seriously unreliable. Like Nita, I am “against prohibitions against genetically modifying babies,” as she describes her own position. Second, I did not “conflat[e].. self-enhancement with offspring enhancement.” Some of the points I made would, of course, apply to both.

Third, far from “sensationalizing” claims about possible designer baby technology, I specifically noted in my post that “[o]bviously, it could turn out that designer babies with vastly increased abilities are technologically infeasible, or at least a long time away.” At the same time, I cited claims by some scientists that designer baby technology could become feasible in the near to medium-term future. I did not endorse or reject those claims, because I lack the scientific expertise to do so. I merely concluded that the possibility that they could be true makes the morality of designer babies worth debating. Readers can judge for themselves whether that qualifies as sensationalism or not.

Nita complains that I overemphasize the role of genetics in intelligence, and notes that a recent study finds that only 20-40 percent of the variation in intelligence is explicable by genetic factors. I did not in fact make any claims about the amount of variation in intelligence explicable by genetics. But assuming the figures Nita cites are correct, it strikes me that 20 to 40 percent is not a small number, and still leaves a lot of room for potential increases in intelligence through genetic engineering (assuming, of course, that it becomes technologically feasible to do so). In addition, even if genetics explains “only” twenty to forty percent of the variation today, it could potentially account for more than that if genetic engineering of intelligence becomes feasible. For example, in a population where the vast majority of people have heights ranging from 5’10” to 6’1,” genetic variation in height would explain only a small proportion of the variance in basketball-playing ability. But if genetic engineering makes it possible for many more people in that population to reach heights such as 6’6″ or seven feet, the percentage of variation in playing ability explained by genetic variation in height would greatly increase. The same could be true of intelligence in a world where genetic engineering enables many more people to attain very high IQs that today are attained by only a tiny fraction of the population. I emphasize the “could” here because I take no position on whether any of this is likely to be technologically feasible. It’s also worth noting (as I pointed out in my original post) that if genetic engineering enables all or most children to reach very high levels of intelligence, then genetics might explain little or no variance (because there will be very little variance in the genetically-determined portion of intelligence at all). But there would still be large gains to both society and individual children, as a result of the increased average level of intelligence.

Finally, Nita states that she takes issue with my “distributive justice claim.” Here, it is possible that we have a genuine disagreement. But I can’t tell if we do, because Nita does not explain how her position on the distributive justice issue differs from mine. If we do indeed disagree, I would be happy to discuss it. Though it may be a while before I can do so, because I will be on the road most of today and tomorrow.

UPDATE: It’s worth noting that the study Nita cites as downplaying the genetic contribution to intelligence actually concludes that “common SNPs explain 22–46% of phenotypic variation in childhood intelligence” and emphasizes that “Results from twin, family and adoption studies are consistent with general intelligence being highly heritable and genetically stable throughout the life course.” I don’t claim that the study is necessarily correct, and it certainly does not indicate that intelligence is completely determined by genetics. But I didn’t make any such claim in my original post either.