Will neo-eugenics spread? Probably. At least it is hard to see what will stop it if, as I claim, it becomes possible to detect all known disease-causing mutations before birth or implantation, if the cost of IVF and PGD declines, and if eugenic screens have clear economic benefits. Some readers might find it peculiar that in this discussion of neo-eugenics, I have not considered the ethical or legal implications with which this subject is generally considered to be fraught. Although I do not doubt their importance, I simply have no particular knowledge of them. Peter Medawar put it best 40 years ago: "If the termination of a pregnancy is now in question, scientific evidence might tell us that the chances of a defective birth are 100 percent, 50 percent, 25 percent, or perhaps unascertainable. The evidence is highly relevant to the decision, but the decision itself is not a scientific one, and I see no reason why scientists as such should be specially well-qualified to make it" (Medawar, 1966).What Leroi is saying is that it will be economical to test all known disease causing mutation on the cheap. Right now it is possible to test such mutations individually, but the cost and ease of testing for all of them is too steep.
Of course, this raises important issues for parents. Chances are that random recombination will result in embryos having at least some of the genetic susceptibilities of their parents. So, while parents will be able to choose which babies they don't want, they won't be able (at least easily) to custom-order "perfect" babies, i.e., those that score negatively for all disease-causing mutations.
EMBO reports 7, 12, 1184–1187 (2006)
The future of neo-eugenics. Now that many people approve the elimination of certain genetically defective fetuses, is society closer to screening all fetuses for all known mutations?
Armand Marie Leroi