Concept 14 Mendelian genetics cannot fully explain human health and behavior.

Mendelian genetics cannot fully explain human health and behavior.

There was obvious interest in applying Mendel's laws to agriculture. Mendel's ideas were also embraced by the eugenics movement, the goal of which was to improve the human species by better breeding. Eugenicists encouraged marriages between people of "good" genetic stock, and discouraged reproduction of the "genetically unfit."

Eugenicists wrongly used simple dominant/recessive schemes to explain complex behaviors and mental illnesses — which we now know involve many genes. They also failed to account for environmental effects on human development. In the United States, restrictive eugenics legislation reflected political and social prejudices, rather than genetic facts. The eugenic description of human life was finally discredited by the horrible consequences of the Nazi quest for racial purity.