This chapter looks at how the science of body measurement (anthropometry) developed by anthropologists was taken up in the medical field to arrive at a concept of female genital normality, and to identify states of health and disease in the female body. Specifically, it draws on the genital taxonomy of a French gynaecologist by the name of Félix Jayle, who produced highly detailed categories of vulval types from measurements taken from his female patients. This text is noteworthy for the empirical attention Jayle paid to the size and shape of the external female genital structures, and for his novel method of categorising the labia minora into four distinct types. Importantly, Jayle proposed that the ‘hypertrophic’ type was specific to black women and that its appearance in white women was a sign of racial degeneration. The chapter argues that Jayle’s contribution to the medical definition of labial hypertrophy came out of the deeply racist framework of twentieth-century eugenics.