In this chapter, I will explore existing models for sex and gender in order to challenge those modes of understanding, particularly in how they influence medical understandings of identity and embodiment. Much of the conversation around validating trans people focuses on the difference between sex and gender as concepts and on challenging the limited, binary definition of those two terms (Valdes, 1995). Sex is often framed in a heavily gendered way, contributing to a pervasive belief that sex and gender are interchangeable and that sex determines gender. Therefore by clearly separating gender from sex the connection that gender has to the physical is called into question or even disavowed, thus seemingly accounting for trans existence. Judith Butler sums this stance up thusly: ‘Originally intended to dispute the biology- is- destiny formulation the distinction between sex and gender serves the argument that whatever biological intractability sex appears to have, gender is culturally constructed: hence, gender is neither the causal result of sex nor as seemingly fixed as sex’ (1990: 8).

For example, I may have a ‘female’ body and have been assigned the female sex at birth, but because gender and sex are separate concepts my masculine gender identity can be validated in its separateness from my sex. However, this separation promotes narratives that fail to accurately describe the diverse experiences of trans people. In this chapter I will argue that the best model for understanding sex and gender is in fact to understand them together, as deeply entwined concepts that constantly co- create each other. I unpack how sex is already understood through the lens of gender and the different problematic models for transness which that understanding leads to. This is not an argument to do away with the concept of gender altogether, but by understanding that sex is just as socially constructed and self- identified as gender and how gender and sex influence each other we can better understand the diversity of the embodied human experience.