That line of thinking goes back even further than the nazis, being quite a respectable scientific point of view in the late 19th/early 20th century.The americans were very big on eugenics, many many people were sterilised on the most spurious of grounds,but with the most impeccable scientific justification. Scientific consensus in many cases(and it should be judged on a case by case basis)is no better than that of a random sampling of blokes down the pub.
