Abstract: The folk take sex categories to be exhausted by the binary of male and female, but this sits badly with the biological reality of intersex conditions. Alison Stone has argued that we should adopt an HPC (homeostatic property cluster) account of sex categories so that we can accommodate intersex and transsexual individuals, without having to reject biological realism about the kinds male and female. I'll argue that HPC theory is not well suited to the work Stone asks of it, and that the biological facts don't force the male/female binary on us.