History of Eugenics in Otorhinolaryngology: Ernst Rüdin and the International Eugenics Network.

Introduction  The early geneticist and psychiatrist Ernst Rüdin (1874-1952) became one of the key figures in the eugenics movement and in the German health system of the Nazi era. His connections in the international eugenics network have played an important role in the history of eugenics. Objective  To discuss the connections between Ernst Rüdin's scientific group in Munich and Otmar von Verschuer's group in Frankfurt during the Nazi era. Methods  Otorhinolaryngological materials from Ernst Rüdin's former private library are presented, and they show Rüdin's deep involvement in the international eugenics network. These materials provide insights into early medical genetics in otorhinolaryngology. Results  One result of the present study is that eugenics groups from Munich, Frankfurt, and New York certainly influenced one another in the field of otorhinolaryngology. Karlheinz Idelberger and Josef Mengele were two scientists who performed hereditary research on orofacial clefts. Later, Mengele became deeply involved in Nazi medical crimes. His former work on orofacial clefts clearly had, to some extent, an influence on subsequent studies. Conclusion  An international eugenics network already existed before 1933. However, it becomes clear that the weaknesses of many early genetic studies did not enable its authors to draw firm scientific conclusions, suggesting that scientists lacked an accurate concept of the genetic causes of most illnesses.