This article examines two disputes within sex and gender movements, using them to think through inclusion/exclusion processes, the place of such explosions in the construction of collective identity, and the gendered nature of social movements. Literatures on collective identity emphasize the ways boundary negotiation reinforces the solidarity necessary for collective action and note benefits of solid boundaries, yet downplay the role of internal conflict in the making of collective identities. The cases examined here both involved the explicit expulsion of some (...) “members”: the North American Man/boy Love Association from the International Lesbian and Gay Association, and transsexuals from the Michigan Womyn's Music Festival. An incongruence between practical participation and symbolic exclusion suggests that internal movement debates are best understood as public communications, depending heavily on the communicative environment. Finally, these stories raise questions about the gendered nature of collective identity construction in social movements more generally. (shrink)