Eugenic considerations also lay behind the adoption of incest laws in much of the U.S. and were used to justify many anti-miscegenation laws. [44] Stephen Jay Gould asserted that restrictions on immigration passed in the United States during the 1920s (and overhauled in 1965 with the Immigration and Nationality Act) were motivated by the goals of eugenics.
it was used to justify by breeding out people with diseases and disabilities and other characteristics that were 'undesirable' and people that agreed with this thought that those type of people were to be bred out of the gene pool
