In 'Against Physiognomy' (非相), Xunzi draws a distinction between the concepts of 'male and female' (牝牡) and those of 'man and woman' (男女), and argues that only human beings (as opposed to mere beasts) are capable of distinctions like the latter. We will consider Xunzi's comments on gender in the broader context of his views about the origins and purposes of social distinctions in order to both reconstruct Xunzi's views about the metaphysics of gender, as well as to explore what else a Xunzian metaphysics of gender might be.