During the early 20th century, observations of the familial nature of behavioral disorders led some scientists and social theorists to develop the now discredited eugenics movement. Eugenics was a misguided attempt to implement social control over human reproduction. People with a variety of psychiatric and developmental conditions were encouraged to undergo voluntary sterilization in the United States and Europe.54 Under the Nazis in the 1930s and 1940s,55,56 eugenics was used to justify programs of euthanasia in psychiatric hospitals.
