eugenics

A pseudo-science based on the belief that the genetic quality of a human population can be improved by promoting certain desirable traits and reducing undesirable ones. Eugenics, which is highly influenced by racism, had many proponents in the early 20th Century in Europe and the United States. Advocates of eugenics promoted discriminatory policies such as restricting interracial marriage or forcing the sterilization of individuals deemed "unfit" (often those with mental illnesses or disabilities). Principles of eugenics also influenced immigration policies, limiting entry for individuals of certain ethnic or racial backgrounds, often based on nationality.