Many theorists believe it can if there is a shared understanding of what women have in common. One possibility, developed by Naomi Zack in Inclusive Feminism: A Third Wave Theory of Women’s Commonality (2005), is that all women share a relation to an historical category that has been oppressed: the group of mothers, or birth females, or men’s heterosexual choices. A second, developed by Cressida J. Heyes in Line Drawings: Defining Women Through Feminist Practice, is that women share Wittgensteinian “family resemblances.”