The social policies of eugenics in Nazi Germany were composed of various ideas about genetics. The racial ideology of Nazism placed the biological improvement of the German people by selective breeding of "Nordic" or "Aryan" traits at its center. These policies were used to justify the involuntary sterilization and mass murder of those deemed "undesirable".
Eugenics research in Germany before and during the Nazi period was similar to that in the United States, by which it had been heavily inspired. However, its prominence rose sharply under Adolf Hitler's leadership when wealthy Nazi supporters started heavily investing in it. The programs were subsequently shaped to complement Nazi racial policies.