Nazi Germany and principles of eugenics
Eugenics was very popular in Europe in the first decades of the XX century. Its followers believed that qualities such as the propensity to alcoholism, moral turpitude, and even poverty - are inherited traits, and to deal with them only by means of the selection criteria. In practice, this meant the forced sterilization and abortion have "undesirable" human society.
Eugenics is to some extent offset the lack of such sciences as psychology and genetics. Nazi Germany was based on it, selecting some and killing others to achieve "racial purity." Guided by the same principles of German medicine, conducting cruel experiments on humans in an attempt to bring the "ideal" person.
Nazis ruined the reputation of the teaching of eugenics, and the development of science and society in general contributed to the principles of eugenics were considered unethical and teaching ceased to exist.