Is the “real” problem with eugenics the principle, or the coercion?
The heritability of physical and psychological traits is not generally disputed among behavioral geneticists or evolutionary biologists. Indeed, the very equations we use to forecast the effectiveness of breeding programs depend partly on the heritability of traits, and those equations apply as much to people as they do to plants. It is no great secret why commentators and scientists dutifully avoid this topic, though. To discuss breeding in any organism besides humans is merely academic, but to toss Homo sapiens into the mix is to harken back to the horrors of eugenics. Fear of this topic (and disgust towards it) is understandable. At the same time, it seems reasonable to try to parse out why people initially thought it important to be concerned with human breeding, and also how that concern was mistakenly translated into atrocity and murder.