Homosexuals were among those persecuted in nazi Germany. Various researchers have explained this in terms of National Socialist racist ideology and eugenics, because the, nazis justified their regulations on the basis of population policies. They were apprehensive at the appearance and spread of homosexuality because it would result in larger numbers of Germans no longer procreating. This persecution was inevitable and massive, so the argument runs, because in the Third Reich, sexuality above all served propagation, population expansion, biological health and the purity of the so-called 'Aryan' race.' Medical historians have characterized the nazi regime as a 'biocracy': major social and political issues like the Jewish 'question', ethnicity, gender, poverty, crime, 'asocial' behaviour and sexual deviance, were transformed into and reduced to biological and medical problems, for which there were apparently 'neutral', technical solutions. The willingness of the German medical profession to embrace the National Socialist cause was substantial, and biomedical scientists played an active role in the initiation, administration and execution of nazi 'biopolitics'. Thus it has been argued that the nazi biocracy was based on a strong affinity of the intellectual and social structures of professional medical science with authoritarian politics. The more science became expert knowledge and the domain of privileged professionals and a technocratic elite, the more it was conceptualized as undemocratic. Refuting the current notion that nazism corrupted, distorted and misused a supposedly neutral biomedical science, these authors assert that biology and medicine were already inherently politicized and that they lent nazism a specifically scientific and technocratic character. Employing a rhetoric of medical emergency, many leading nazis indeed saw their politics as applied biology. In their biomedical worldview, the German people suffered from deadly diseases. Their 'cure' was racial purification that would progress from coercive sterilization, euthanasia, segregation, and concentration for supposedly 'hygienic' reasons, to direct medical killing and genocide. From the notion that racial hygiene, the nazi vision of a 'total cure' by means of a medically oriented purification, dictated their treatment of homosexuality, it was only a small step toward bracketing homosexuals with Jews, the Sinti and Roma, ethnic minorities, psychiatric patients and hereditarily ill people as principal victims of nazi terror. However plausible this explanation may sound, it is neither entirely convincing nor complete. In the first part of this article that discusses the reili.l between biomedical science and nazi politics, I shall indicate why it is not satisfactory. In the second part I shall then attempt to give an additional explanation for the nazi persecution of homosexuals. This explanation focuses on the threat of homosexuality perceived by some important nazi leaders within their all-male military organizations. During the nazi regime the tension between male bonding in German nationalism and latent homoerotic tendencies of the so-called Mannerbund was pushed to extremes.