The science of eugenics, or classifying and grouping people into the categories of genetically “inferior” and “superior” thrived during the first two decades of the 20th century in America. Eugenics argued that the undesirable “inferiors” of America (immigrants, people of color, poor people, unmarried mothers, the disabled, the mentally ill, etc.) must be identified and controlled so their inferior hereditary traits could not spread within America. Proponents of eugenics promoted their ideas to the American people as being necessary for the future wellbeing of the country. In America, the outward acceptance of eugenics resulted in marriage laws enacted, immigration laws put in place, and state-sanctioned involuntary sterilization laws legalized. Ultimately, the American eugenics movement of the 1920s culminated with the decision of Buck v. Bell, which affirmed the eugenic fear of human differences as something that needed to be controlled by American Law.