“The difference between being male and female is that the former are born with an XY chromosome and the latter with a XX chromosome.”

The first time I heard of biological sex delineated along chromosomal lines was in my ninth-grade biology class and, at the time, I believed that was all there was to the science of sex (and consequently, gender). I didn’t probe, nor did I question. I just assumed that the science taught in school was rigorous enough to prepare us for the complexities of biological sex, and boy, was I wrong. It turns out that in an attempt to keep things simple, our textbooks and our conversations have created a false narrative around sex and gender, which is responsible for a lot of the confusion surrounding alternative identities today. 

Let’s start by addressing the elephant in the room—chromosomes. Yes, it is true that sex is often understood in terms of mutually opposed binaries (male and female) underpinned by differences at a chromosomal level. However, this isn’t necessarily the most accurate way of determining sexual delineation. Instead of looking at sexual determination as a linear process, it would be better to liken it to a pathway. The pathways to being male/female are far from distinct. They’re enmeshed in one another—with the genes involved being the same and new variations being thrown around constantly due to evolutionary requirements. 

What does this mean for human beings? Well, we all start as sexually neutral upon conception and stay the same up to the six-week mark when something triggers the male or female pathways, resulting in the sexually indifferent gonads acquiring male or female characteristics. In simple terms, regardless of our chromosomes, it takes a trigger to lead us down a particular path. This trigger is called the SRY gene. This gene is the instruction manual for producing sex-determining region Y protein. This protein is essential for male-typical sex development. If a foetus lacks this gene or if it suffers a mutation, you have a complicated situation where chromosomes paint a picture that reality doesn’t match. Suddenly, the binary no longer makes sense because biology isn’t linear or convenient. 

One need only look at nature to see just how convoluted the processes of sexual differentiation can be. In fact, I would argue that if we spent just a little more time examining how whacky biological sexual determination is in nature, it would make being open-minded a much easier task.

Here are some of my favourite examples of nature doing its thing regardless of the binary-based image of reproduction and sexual determination we humans have: 

Hermaphrodites across the animal kingdom are a prime example of nature having a good time. The organisms are either born with both male and female reproductive organs (snails, slugs and earthworms) or can change their reproductive role during their life cycle depending on the ratio of females in their local population (clownfish, slipper snails, sea bass).

All female garden moles possess an ovotestis i.e.; their gonads are composed of both ovarian and testicular tissue. This combination means that when their ovarian tissue is not pumping out eggs during breeding/mating season, their testicular tissue is producing an insane amount of testosterone, making their vaginal canal close up and their behaviour hyper-aggressive (which comes in handy while protecting their litters). This form of “true hermaphroditism” is rare in humans but not impossible. So intersex-people deniers can suck it!

Turtle sexual determination has more to do with temperature than the fertilization process. Research has shown that the sex of a turtle’s offspring depends more on the temperature in which the egg is incubated. Common in turtles, alligators and crocodiles, the term for this is temperature-dependent sex determination or TSD. How does this work? Well … if the egg is incubated below 27.7° Celsius the offspring will be male, whereas eggs incubated in temperatures over 31° Celsius produce female offspring, which is bound to create an interesting scenario given the rising temperatures from climate change, so keep an eye out for more news about that. 

The lesbian leaping lizards, however, cannot be left out of this conversation. The New Mexican Whiptail reproduces asexually via parthenogenesis (producing an embryo without fertilizing the egg with sperm). The absence of new genetic material during the “reproduction” process means these female lizards are, essentially, cloning themselves, repeatedly! Thanks to the hybrid nature of this species, the males are sterile.

Unlike most mammals in the animal kingdom, platypuses have an inordinately complicated chromosomal structure. Nature’s weirdest mammal gets even weirder when you realise that they have five pairs of chromosomes, which form a chain-like structure where the X and Y chromosomes pair up in an alternating fashion and then get segregated into two groups, resulting in sperm cells that either carry five X chromosomes (female) or five Y chromosomes (males). It’s all very complicated.

And that’s the point I hope I’ve made through this article. Science is complicated, and we would be remiss in assuming that either was simple because we want both to fit into our larger social narrative. So when in doubt about what is or is not possible in human beings or, better yet, what is and is not NATURAL for human beings, look at nature in its entirety, please. Hopefully, it’ll give you some perspective.