Sexual Spectra: Biology and Sexual Politics in Europe, 1896-1933

In contrast to those who would argue that conceptions of non-binary sex are new, historians of science and gender have shown that definitions of biological sex are just as subject to historical change as any other human idea. Although scholars disagree on when and why the ‘binarist’ view emerged, they generally agree that by the nineteenth century the idea of biological sex as a rigid binary had become a standard assumption of medical knowledge, and that this assumption has persisted to recent times. However, I argue that this historical narrative leaves little room for attending to the fact that some nineteenth- and twentieth-century thinkers conceived of biological sex in non-binary terms. Consequently, such thinkers have tended to be either ignored or studied in isolation from each other, creating the impression that their deviations from binary sexual thinking were abnormalities. In this dissertation I challenge this view through a history of conceptions of biological sex showing that the idea of sex as a (non-binary) spectrum was quite widespread in late-nineteenth- and early-twentieth-century Europe. Taking recent developments in the study of gender and sexuality as a starting point, I also argue for the importance of biological sex as a useful category of historical analysis. Indeed, my research suggests that these thinkers of a century ago, and their conceptions of scientifically-grounded sexual fluidity, might well be relevant for reconceptualizations of biological sex in gender and trans theory today.