Nazi eugenics ( German : Nationalsozialistische Rassenhygiene , "National Socialist racial hygiene") were Nazi Germany 's racially based social policies that placed the biological improvement of the Aryan race or Germanic " Übermenschen " master race through eugenics at the center of Nazi ideology.  In Germany , eugenics were mostly known under the synonymous term racial hygiene . Following the Second World War , both terms effectively vanished and were replaced by Humangenetik ( human genetics ).
But the concept of a white, blond-haired, blue-eyed master Nordic race didn't originate with Hitler. The idea was created in the United States, and cultivated in California, decades before Hitler came to power. California eugenicists played an important, although little-known, role in the American eugenics movement's campaign for ethnic cleansing.