The article reconstructs the emergence of institutionalized research programs in the field of psychiatric genetics. It focuses on the first institutions in this field in Germany, the United Kingdom, and the United States: the Genealogisch-Demographische Abteilung (GDA) at the Deutsche Forschungsanstalt für Psychiatrie in Munich founded in 1917/18; the Program (later: Department) of Medical Genetics at the New York State Psychiatric Institute, associated with Columbia University, and founded in 1936; and the Psychiatric Genetics Unit at the Institute of Psychiatry in London, founded in 1959. The early protagonists which today are considered the founding-fathers of this field in Britain and the USA, Eliot Slater and Franz Kallmann, both had been research fellows at the Munich GDA in the mid-1930s which at that time was directed by Ernst Rüdin. Rüdin was perceived as the leading personality in the field internationally; at the same time, he was one of the protagonists of the German movement of eugenics and racial hygiene, and after the Nazi-takeover in 1933 closely co-operated with the regime in regard to health and racial policies. The contribution documents that not only Rüdin, but also Kallmann and Slater throughout their career in medical genetics until the 1960s were motivated by eugenic ideas, and engaged in eugenic organisations, - however, with different consequences, and in different political contexts. It is further argued that these eugenic motivations had repercussions on the topics and questions pursued in the protagonists' genetic research.