Eugenics was a practice to improve human population by genetic compositions. It generates the idea in social philosophy that human heredity traits can have more deisrable reproductions and the less desire people and trait can be reduced. It has a connection with Charles Darwin's Theory of Evolution where Darwin states how the fittest survives. This is a very controversial subject as it brings up segregation and racism. It also embeds in to the history of Nazis and the Holocaust. Eugenics brought identification that classified families and individuals which were categorized by the metally ill, poverty stricken, disableds, homosecuals, entire racial groups (Roma and Jews) and much more. To "sterilize" in the case of Nazis used methods such as extermination.
Eugenics was first thought out by Francis Galton, Karl Pearson, and others. Both wrote in their book Hereditary Genius that racial improvement was possible in a scientific way. The eugenic connection quickly became internationalized after the two had gotten established a Eugenics Laboratory sponsored by University of London in 1904. The spread of this idea was especially wild fire across the European nation and the first international confress of Eungenicist was held in London in 1913.
The founding father of Eugenics in the US was C.B Davenport. Davenport quickly became a significant advocate of immigration limitation and of sterilization. Sterilization were aws that were against ethnic minorities rather than against the white members. The steriization measures that were brought out by the national socialists during the 1930s and the Holocaust link directly back to the propaganda of Eungenics in the 20th century.
Sterilization policy soon got passed in most of the European states.
It was really shocking to see that what happened in Germany and elsewhere all had a meaning, a method, a theory, and a philosophy behind it. It is I think overlooked that science had to really do with how people reacted to in this case Eugenics.
(Pratt Data base PDF)