The history of the concept of degenerationism is traced from its beginning with the work of Morel in 1857. This theory asserts that hereditary elements in certain families or races cause ever-increasing physical and/or mental deterioration, leading to the extinction of those families or races. Throughout his career, Freud attacked the theory of degenerationism, downplaying the role of heredity, and emphasizing instead the impact of early experience and trauma: a humane emphasis on the importance of respect and tolerance for the individual, and a hopeful attitude toward the possibility of therapeutic change. The use of notions of degenerationism by the Nazis is described, and we are cautioned to be alert to any current assumptions of biologic elitism.