I argue for a deflationary answer to the question, “What is it to be a woman?” Prior attempts by feminist theorists to provide a metaphysical account of what all and only women have in common have all failed for the same reason: there is nothing women have in common beyond being women. Although the social kinds man and woman are primitive, their existence can be explained. I say that human sex difference is the material ground of systems of gender; gender (...) systems serve to enable male control of female reproductive capacities. This explains the fact that most women are female, but it does not entail that all women are female or that all females are women. To clarify my position, I draw an analogy between the kind woman and the kind parent. While it is difficult to come up with necessary and sufficient conditions for being a parent, it is clear that the social institution or practice of parenting has its material ground in the biological facts about human reproduction together with facts about infantile dependency. Saying this does not entail that all and only biological progenitors are parents. (shrink)