You’ve likely heard the old adage, “Men are from Mars; women are from Venus,” a pithy proverb created to communicate that, in many ways, men are demonstrably different than women. We have different bodies, different proclivities, different stereotypes. For a long time, it was basically just assumed that many of our most pronounced differences were the result of having a male or a female brain.

It’s a hot button discussion that has resurfaced in recent history as scientists attempt to prove that individuals who claim transgender status have brain maps more consistent with their expressed gender identities. In short, they are saying that men who believe they’re women have female brains and vice versa. It’s puzzling to note that these people seem to believe the brains can determine gender, while genitalia’s determination of sex is simultaneously irrelevant.

The “studies” used to peddle this ideology are questionable, at best, with minute sample sizes and big gaping holes in addressing important variables. The fundamental problem with these types of assertions is that, in reality, brain science is anything BUT settled. There’s no scientific consensus on the notion of a male or female brain. If you were to closely examine the brains of both sexes and compare them to one another, it’s unlikely you would be able to discern any differences between them whatsoever. The male brain might be slightly larger. Certain regions in the female brain MIGHT have thicker cortices, but again, they might not. There is no consistent, ever present discrepancy between the brains of both sexes.It’s just not there. In order to claim to have a female brain, one would first have to define how a female brain is consistently different from a male brain. Do you see the dilemma?

Brain science is inconclusive for a number of other important reasons. It’s nearly impossible to isolate the variables in play. Are men’s and women’s brains really different, or are the different responses a result of exposure to different hormones? How does socialization factor in? Could it be that men and women are conditioned to respond differently and that our brains adjusted to the demand?

We know, for example, that females have twice the lifetime rates of depression and anxiety disorders. It’s worth noting, but we can’t conclusively frame this data as proof that women’s brains themselves are dramatically different than men’s. We have to take a more comprehensive approach and account for all the other factors such as exposure to sex-based abuse or violence, social stigma, etc.

And let’s assume for a minute that trans identified peoples’ brain maps ARE consistently different than the brain maps of other members of their sex. What should we make of this? Does this mean we should behave as though the variance is a great thing, or is there room to try to resolve the dissonance? We know that people who struggle with anorexia often have unusual brain scans. So do sociopaths. So do children on the autism spectrum. Are we to just behave as though anorexia is the norm, that people are born that way, and that we should embrace it as a healthy lifestyle choice? Or are there other better responses to the information with which we’re presented?

While we cannot yet definitively declare concrete and major differences between men’s and women’s brains themselves, new studies are emerging to invite further exploration of some more specific differences in brain activity.

One such study examines how the brain’s gene activity impacts the sex-specific behaviors of mice. Though the studies were not conducted on humans, scientists assume the findings would be pretty close to parallel on human subjects. In this study, scientists probed four tiny structures within mouse brains that are known to program “rating, dating, mating and hating” behaviors.

We will pause here to draw attention to the fact that one of behaviors analyzed was the quick determination of a stranger’s sex. In mice, this behavior is classified as instinctive, but when humans follow these same instincts, we are often accused of transphobia and disingenuously asked how we could possibly assume what genitalia the person has. But we digress…

The scientists analyzed tissue that was extracted from certain parts of the brain structures and found more than 1,000 genes that were substantially more active in one sex than the other, and of these, several hundred were entirely dependent on the females’ menstrual cycle.

The study goes on to report, “Some of the genes the researchers catalogued are established risk factors for brain disorders that are more common in one or the other sex. Of 207 genes already known to confer high risk for autism spectrum disorder, which is four times as common in men as in women, the researchers identified 39 as being more active in the brains of one or the other sex: 29 in males, 10 in females. They also identified genes linked to Alzheimer’s disease and multiple sclerosis, both of which tend to afflict women more than men, as being more activated among female mice.”

So what do we make of this?

It serves to confirm what we already largely knew; the brain itself may not be a sexed organ, but it responds specifically to the myriad other sexed characteristics and processes of the body, all of which work in tandem with each other. It tells us that male and female are a matter of biological sex, not subjective feelings. It tells us that the difference between sexes is consequential in countless ways we could never imagine. And it tells us that, if we truly care about science, we have to operate within the terms of material reality, which, for both humans and mice, is a sexually dimorphic experience.