This article presents a case study about how norms relating to masculinity, sexuality and reproduction were produced in relation to the healthy, ailing, or aging prostate in early twentieth century medicine. It shows how the ailing prostate tied in with norms about healthy, abnormal or illicit sexual and reproductive practices. Engaging with insights from the history of medicine, feminist science studies, and men and masculinity studies, it highlights how the prostate became a diagnostic catch-all for a wide range of physical and mental conditions, producing demarcations between femininity and masculinity, manliness and unmanliness, health and illness, and moral and vice. … the prostate is not only a sexual organ, but one that is absolutely indispensable … without it the race would end and without it the pleasure of sexual contact would be wanting. 1 George M. Phillips, 1903 What is a prostate? In the early twentieth century, medical practitioners provided a variety of answers to this question. The gland's connection to men's reproductive systems was widely agreed upon at the time. Medical professionals, such as the professor of genitourinary surgery quoted above, considered it to be vital for conception and thus the future of the human race. Others saw important connections between the prostate and a man's general health and wellbeing, both physical and mental. In scholarly articles and clinical reports about men and their prostates, professionals explored and debated physiological qualities and problems related to the gland. At times, such accounts included material that outlined norms around masculinity and sexuality; the prostate spoke to what it meant to be a man, a husband and a productive citizen. This observation aligns with the more general pattern shown by scholars studying the prostate and related aspects of men´s 'intimate health' during the early twentieth century, that such accounts could be 'heavily moral in tone'. 2 The introductory quotation above comes from Professor George M. Phillips, one of the medical practitioners who, in the early 1900s, argued that the prostate gland played a crucial role in men's health and wellbeing far beyond its reproductive