Early in his career the famed evolutionary biologist William D. Hamilton had a strong interest in eugenics. In his autobiographical collection of papers Hamilton admits that he suspects these tendencies were the reason for the suspicion he aroused in some of the more senior scientists in Britain after World War II. But Hamilton later also admits that his earlier enthusiasms for social engineering through selection for “good traits” may have been wrong-headed, insofar as the selection pressures of evolution are protean, and what may be adaptive perfection in one age may be doom in another (or, in the world of international migration, you can substitute place for time). This does not mean that Hamilton abandoned his worry about increased “genetic load” in the human population (deleterious mutations accumulating in the human gene pool because the “unfit” now live and breed thanks to modern medicine). It is simply that such ideas and concerns can’t be easily reduced into simple formulas and maxims, because evolutionary processes can vary in their implications over time and place.

I thought of these issues when stumbling upon this curious comment over at Genetic Future in regards to preimplantation genetic diagnosis:

Genetic selection will ...