When it comes to considering sex and gender, don’t forget sex determination

Scientific American “Beyond XX and XY: The Extraordinary Complexity of Sex Determination”

I teach about sex and gender in a lot of my courses. For some courses, such as Evolution or The Evolution of Sex, these are basic concepts that need to be established in order to study reproductive behaviors. For other courses, such as Breeders, Propagators, & Creators, a nuanced understanding of sex and gender makes it possible to unravel the complexities of the human species’ dual inheritance systems and their influence on how we behave. And getting sex and gender right is not just important academically: some fraction of our students are going to be transgendered, and we need to make sure that the way we talk about sex and gender is both scientifically accurate and culturally sensitive.

I have been working on making sure that my teaching on sex and gender is solid, but after I found the above article and its accompanying graphic, I realize that there has been a bit of a hole in my teaching. It’s fine to talk about gender and its distinction from sex, but a failure to define sex as not just “male” and “female” but also “intersex” risks getting the biology wrong… and, more importantly, failing to validate the experience of some of our students.

Please check out the graphic on the Scientific American page. It highlights the many pathways by which people can be develop intersex characteristics. The presence of each of these pathways may not be all that common in the population, but students should be aware of them. Talking about intersex development is also a great way to highlight how complex a process sex determination is, and to prompt students to consider that being born with a 46XX or 46XY chromosome configuration is no guarantee of developing a narrow range of “one side of the binary or the other” characteristics. And these intersex developmental patterns — all of which disrupt some element of the developmental pathways that lead to male and female characteristics — are just the more obvious and detectable deviations from the biological sex binary. Their existence should make us all question what other more subtle variations in development might create broader variation in what it means to be “male” or “female”.

This is not a popular position in some circles, but I think that our biology plays a role in our gender presentation. The fact that we acknowledge that people are sometimes “born identifying” with a particular gender should allow us to see that most people realize that gender presentation is not just something you learn culturally. The fact that sex determination is so complex adds a wrinkle to this story: it suggests ways that variations in sex determination might lead to a larger spectrum of male and female traits than we might otherwise acknowledge by assuming too strong a sex binary. Sure, I think that the culture that one develops within ultimately determines what gender presentations are considered “normal” and how free a person is to express their gender identity. But some really glorious and variable interaction between genes and the environment produces the developmental processes that lead to the individual behaviors we then assign to gender. Sex and gender are all mixed up with each other, even if they are separate concepts.