Drawing from our qualitative, in-depth interviews of 35 professionals who write referral letters for "gender transition," we explore how practitioners' decisions to approve, delay or refuse access to body modifications speak to the centrality of normative concepts of sexuality and the social function of bodies in the cultural politics of gender identity. We argue that practitioners construct what we call an ethic of body modification that tends toward reducing the body to its symbolic function-as a representation of the subject's true gender and a basis for sexual identity. We also discuss the views of a minority of practitioners who resist this tendency by creating an alternative path for body modification independent from identity claims. We conclude by discussing the cultural/political implications of pseudo-scientific discourses that assume gender identity is natural, stable and universal, whereas bodies are flexible and malleable social representations.