Gosney was born in Kenton County, Kentucky in 1855, and received a degree in law from the Saint Louis University School of Law in 1880. He settled in Flagstaff, Arizona where he was involved in the establishment of a Wool Grower's Association. Around 1905 he relocated to Southern California, eager to escape the "wild west" environment still present in Arizona while raising two daughters. There he became an active participant in the Pasadena, California business community, especially in the acquisition of citrus and other agricultural crops. Around this time he also became active in the establishment of the first California council of the Boy Scouts of America. He also donated $12,500 to Polytechnic School in 1907 to found the school. By the 1920s he had built up a considerable fortune, owned one of the largest lemon groves in the state, and served as the director of numerous banks, trusts companies, and corporations. While working in Pasadena he became acquainted with the biologist and eugenicist Paul B. Popenoe, and in 1925 Gosney financed Popenoe's collection of data on the implementation of California's eugenic compulsory sterilization laws. At the time, compulsory sterilization was seen by many as a way to reduce the incidence of mental illness and mental retardation in the population over time. Many states had legislation requiring the sterilization of patients at state-run psychiatric facilities, though only California executed the laws in earnest, as most other state officials were wary about the legal status of compulsory sterilization legislation. The result of Gosney and Popenoe's research was a co-authored volume, Sterilization for Human Betterment: A Summary of Results of 6,000 Operations in California, 1909–1929, completed and published in 1929. The book sought to argue that eugenic sterilization was scientifically supported, caused no harm to patients, and was legally sound. The book, distributed widely by Gosney, was used to promote compulsory sterilization legislation in other states and countries, and along with work by Harry H. Laughlin was one of the most influential texts on sterilization in the United States. Gosney and Popenoe's book was specifically referenced by officials in Nazi Germany in the creation of their own sterilization legislation in 1933 as having provided them with proof that sterilization programs could be safe and effective. According to a U.S. health official at the time who had just returned from a trip to Germany, "the leaders in the German sterilization movement state repeatedly that their legislation was formulated only after careful study of the California experiment." Gosney and Popenoe believed the population of mentally ill in the United States could be reduced by half in "three or four generations." The Sacramento philanthropist/eugenicist Charles Goethe wrote to Gosney in a letter from 1934: A follow-up study, Twenty-eight Years of Sterilization in California was published by the pair in 1938. The state of California would eventually sterilize over 20,000 patients in state-run hospitals under its eugenic laws; Nazi Germany would sterilize over 400,000. In 1926, Gosney first began to organize what would by 1928 become chartered as the Human Betterment Foundation as a philanthropic foundation to promote research and advocacy of eugenics, especially by means of sterilization. As Gosney put it, the Foundation would work for: The initial board of trustees was Gosney, Henry M. Robinson, George Dock, David Starr Jordan, Justin Miller, Otis Castle, Joe G. Crick, Goethe, and Popenoe. Later members included Lewis Terman, William B. Munro, and University of California, Berkeley professors Herbert M. Evans and Samuel J. Holmes. The Foundation also established links with the California Institute of Technology, with Nobel Prize-winning Caltech physicist Robert Millikan joining the board of the HBF in 1937. The Foundation published a number of pamphlets and financed continued studies of the California sterilization program through the 1930s, and sent thousands of letters to teachers, libraries, and physicians advocating eugenic sterilization. It also underwrote a column in the Los Angeles Times on "social eugenics" and financed a radio program as well as hundreds of popular lectures around the country. Along with the American Eugenics Society, it was the most active and influential eugenics advocacy group in the country. Upon Gosney's death in 1942, his daughter liquidated the Foundation and donated its remaining assets to Caltech, which in 1943 established a Gosney research fund for biological research using the money. The archives of the Human Betterment Foundation are in Special Collections at Caltech in Pasadena.