Personal Identity, Sexual Difference, and the Metaphysics of Gender [Penultimate Copy. Please Cite Published Version.] Jeremy W. Skrzypek Ohio Dominican University Abstract: Issues pertaining to sex and gender continue to be some of the most hotly debated topics of our time. While many of the most heated disputes occur at the level of politics and public policy, metaphysics too has a crucial role to play in these debates. In this essay, I explore several key metaphysical debates concerning sex and gender through the lenses of two important areas in contemporary metaphysics: the metaphysics of essence and the ontology of the human person. The goal here is not to advocate any particular position on these issues, but to show how the tools of contemporary metaphysics can help to offer a more comprehensive map of the conceptual terrain, indicating where major areas of agreement can be found and where the most important disagreements really lie. Keywords: sex, gender, transgender, metaphysics, essence, personal identity I. Sex and Gender: Asking the Right Questions Issues pertaining to sex and gender continue to be some of the most hotly debated topics of our time. Contemporary debates signal deep disagreements not only over particular policies, practices, and procedures, but also over the very nature of sex, gender, and the human person. In the context of these debates, certain key questions about the relationship between sex, gender, and the identity of the human person have come to the forefront. Can one’s sex and gender conflict, and if so, how are we to understand the nature of that conflict? If a person’s sex and gender can conflict, what is the appropriate course of action in addressing that conflict? Can, and in what circumstances should, a human person successfully undergo a change in his or her sex or gender? The scholarly literature on these issues is vast and bewildering (and one’s bewilderment only increases by considering also the extensive coverage in popular media). So how does one begin to answer these questions? Perhaps the best place to start is by considering the most basic, most fundamental question that can be asked about the two key terms involved: What is sex? And what is gender? Sex is generally (though not exclusively) regarded as a biological category, typically referring to certain