What are examples of eugenics?

Eugenics is "improving" the human race by influencing/controlling reproduction. Examples include the following:

The Immigration Studies Commission formed in California in the early 1920s. The group was founded by Charles Goethe. His goals included restricting the immigration of Mexican nationals into California; he considered those of Mexican heritage to be people of a “low power.” He also supported the sterilization of citizens that were “unfit” for reproduction. Goethe’s definition of “unfit” was often correlated with race and heredity.

In early 1930s Germany, before Hitler took power, the government supported the sterilization of people with hereditary illnesses. Interesting about this project, was that sterilization was only performed on willing participants that agreed to their "unfitness" to reproduce.

Nazi Germany is the most infamous example of eugenics in modern history. Beginning in 1933, the Nazi government instated and supported the Law for the Prevention of Progeny with Hereditary Diseases. This required the sterilization of people with undesirable traits to weed them out of society. These traits included manic depression, hereditary blindness, hereditary deafness, epilepsy and physical deformities.

Eugenics has its roots in social Darwinism. This was a philosophy originating in the 1870s. It attempted to explain social evolution through Darwinian ideas of biological evolution. Eugenics differed from social Darwinism by not just discussing and studying this philosophy, but encouraging the social advancement of some while stifling the social advancement of others.