blank">http://jhered.oxfordjournals.org/cgi/reprint/12/5/219, 1921, depicting it as a tree which unites a variety of different fields.]] Eugenics is a social philosophy which advocates the improvement of human hereditary traits through various forms of intervention. The exact definition of eugenics has been a matter of debate since the term was coined. The definition of it as a "social philosophy" (that is, a philosophy with implications for social order) is not meant to be definitive, and is taken from "Development of a Eugenic Philosophy" by _Frederick Osborn in American Sociological Review, Vol. 2, No. 3 (Jun., 1937) , pp. 389-397. Throughout history, eugenics has been regarded by its various advocates as a social responsibility, an altruistic stance of a society, meant to create healthier and more intelligent people, to save resources, and lessen human suffering. Earlier proposed means of achieving these goals focused on selective breeding, while modern ones focus on prenatal testing and screening, genetic counseling, birth control, in vitro fertilization, and genetic engineering. Opponents argue that eugenics is immoral. Historically, a minority of eugenics advocates have used it as a justification for state-sponsored discrimination, forced sterilization of persons deemed genetically defective, the killing of the institutionalized population and the holocaust.

The modern field and term were first formulated by Sir Francis Galton in 1883, drawing on the recent work of his cousin Charles Darwin. From its inception eugenics was supported by prominent people, including H.G. Wells, Emile Zola, George Bernard Shaw, William Keith Kellogg and Margaret Sanger. G. K. Chesterton was an early critic of the philosophy of eugenics, expressing this opinion in his book, Eugenics and Other Evils. Eugenics became an academic discipline at many colleges and universities. Funding was provided by prestigious sources such as the Rockefeller Foundation, the Kellogg Foundation, the Carnegie Institution of Washington, and the Harriman family. Three International Eugenics Conferences presented a global venue for eugenicists with meetings in 1912 in London, and in 1921 and 1932 in New York. Eugenics' scientific reputation started to tumble in the 1930s, a time when Ernst Rüdin began incorporating eugenic rhetoric into the racial policies of Nazi Germany.

Since the postwar period, both the public and the scientific communities have associated eugenics with Nazi abuses, such as enforced racial hygiene, human experimentation, and the extermination of undesired population groups. However, developments in genetic, genomic, and reproductive technologies at the end of the 20th century have raised many new questions and concerns about what exactly constitutes the meaning of eugenics and what its ethical and moral status is in the modern era.