This essay focuses on “hermaphrodites” to examine how ideas about sexual difference shaped the human-nonhuman distinction in medieval Europe. When constructing a definition of the human, medieval authors repeatedly pointed to a particular kind of sexual difference as a key indicator of humanness: a binary and stable sex, a singular means of reproduction, and a restricted set of possible sexual acts. The boundaries between male and female and animal and human also intersected with how medieval authors imagined boundaries between Christians and non-Christians and Europeans and non-Europeans, who were thought to possess bodily appetites that were more animal than human in nature. During the period, some European texts ascribed hermaphroditic, monstrously misshapen genitals to those living outside the geographic bounds of Europe, linking imagined deviations in anatomy to “race,” a logic that was ultimately applied to Jews and Muslims, and which had a long legacy in both Europe and the Americas. This essay argues that sexual difference is wrapped up in the very taxonomy of the human-nonhuman divide. A turn toward nonhumanism — as modern scholars have proposed in an effort to queer the liberal human subject — is thus not necessarily emancipatory, and in the premodern period it was not. While this essay makes no easy equations between medieval and modern systems of sexual and racial difference, it suggests that engagement with earlier periods of history can help us to think about species difference and its connection to sexual and racial difference in contemporary contexts.