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Feminist Studies 41, no. 3. © 2015 by Feminist Studies, Inc.  Jaye Cee whitehead, Kath baSSett, leia franChini, and miChael iaColuCCi “The Proof Is in the Pudding”: How Mental Health Practitioners View the Power of “Sex Hormones” in the Process of Transition in tHe united states today, popular discourse touts the power of “sex hormones” and hormone receptors in the brain to chemically produce gender expressions (manifested in physical sex traits, behaviors, and attitudes) and identities (a sense of self as feminine or masculine). These accounts range from common assumptions that Western ideals of femininity (such as empathy understanding, cooperative orientation, nurturing behavior) and masculinity (rational/spatial understanding, competitive orientation, violent behavior) are produced by corresponding sex hormones, to studies that reduce complex gender identities and macrosocial economic phenomena to presocial, binary, hormonal processes.1 For sociologists, accounts that reduce complex identities to internal hormonal reactions are problematic for two primary reasons: first, they are inaccurate because they fail to examine how hormonal reactions are embedded in a complex cultural process of meaning and interpretation; second, they operate as bioreductive ideologies that obscure the social power inherent to the process of gender identity construction. In what follows, we extend both of these insights by examining mental health 1. For an example of a hybrid popular-scientific account of the power of sex hormones to destabilize economic structures, see Jon Coates and Joe Herbert , “Endogenous Steroids and Financial Risk Taking on a London Trading Floor,” Proceedings of the National Academy of Sciences 105, no. 16 (April 2008): 6167–72. 624 Whitehead, Bassett, Franchini, and Iacolucci practitioners’ divergent interpretations of the power of sex hormones in the process of gender transition.2 In doing so, we examine the cultural power of sex hormones in crafting gender identities without reproducing reductionist interpretations of trans embodiment. Perhaps what is most perplexing about the way we speak of sex hormones is that we know it is inaccurate to describe these hormones as sexed; scientists have acknowledged since the 1930s that they are neither sex specific in their function, nor in terms of their location in male or female bodies.3 In her extensive historicization of sex hormones, Anne Fausto-Sterling concludes that it is more accurate to call androgen- and estrogen-based hormones, “steroid hormones” as they have functions that are not confined to corresponding sexed bodies. In fact she urges scientists to “break out of the sex hormone straightjacket” and to look at steroids as just one of a number of components that are important to the creation of sex and gender, including environment and experience.4 Scholars also point to an inextricable link between the chemical operation of hormones and the social process of constructing meaning, both at the level of social interaction and macrocultural constructions of sex categories and gender ideologies.5 While brain organization/activation theory attributes sex and gender differences to hormonal interactions within the developing brain, Fausto-Sterling questions the distinction between activation and organization by pointing out how “the brain can respond to hormonal stimuli with anatomical changes…hormonal systems, after all, respond exquisitely to experience, be it in the form of nutrition, stress, or sexual activity (to name but a few possibilities ).”6 Drawing from Elizabeth Grosz, Fausto-Sterling argues that the power of hormones is best understood according to the model of the 2. “Gender transition” is a controversial phrase, as it implies that transgendered individuals who receive hormone therapy are changing identities. We are only using it for lack of clear alternative phrasing, not because we believe body modifications change gender identities. 3. See Anne Fausto-Sterling, Sexing the Body: Gender Politics and the Construction of Sexuality (New York: Basic Books, 2000); Rebecca Jordan-Young, Brainstorm: The Flaws in the Science of Sex Differences (Cambridge, MA: Harvard University Press, 2010); and Nelly Oudshoorn, Beyond the Natural Body: An Archeology of Sex Hormones (New York: Routledge, 1994). 4. Fausto-Sterling, Sexing the Body, 193–94. 5. Fausto-Sterling, Sexing the Body. 6. Ibid., 232. Whitehead, Bassett, Franchini, and Iacolucci 625 Möbius strip, wherein internal components of the self are always connected to and continuous with outer components such as culture and environment.7 In other words...