This essay analyzes one of Germany's former premier research institutions for biomedical research, the Kaiser Wilhelm Institute for Anthropology, Human Heredity and Eugenics (KWIA) as a test case for the way in which politics and human heredity served as resources for each other during the Third Reich. Examining the KWIA from this perspective brings us a step closer to answering the questions at the heart of most recent scholarship concerning the biomedical community under the swastika: (1) How do we explain (...) why the vast majority of German human geneticists and eugenicists were willing to work for the National Socialist state and, at the very least, legitimized its exterminationist racial policy; and (2) what accounts for at least some of Germany's most renowned medically trained professionals' involvement in forms of morally compromised science that wholly transcend the bounds of normal scientific practice? Although a complete answer to this question must await an examination of other German biological research centers, the present study suggests that during the Nazi period the symbiotic relationship between human genetics and politics served to radicalize both. The dynamic between the science of human heredity and Nazi politics changed the research practice of some of the biomedical sciences housed at the KWIA. It also simultaneously made it easier for the Nazi state to carry out its barbaric racial program leading, finally, to the extermination of millions of so-called racial undesirables. (shrink)