Gender and Neurology

by Ava


Recently, I’ve noticed a surge in the amount of people who say that gender is a social construct. I’ve been hearing this everywhere: not just in the depths of tumblr.hell, but also on nicer parts of the internet and even from people I know in real life. This got me thinking, and after a bit of research I concluded that I do not agree with this statement.

In this article, I’m going to use scientific articles (all sources listed at the bottom of the page) to back up my opinion on this issue. However, although I think that gender is biological, I will also be arguing the point that transgender people are perfectly valid. This will become clear later on in the article.

In order to see how gender is developed, we have to look at the very first life stage of a human being. You may have heard before that every fetus starts off as a female, and although that is simplifying the matter a little bit, it is essentially true. A fetus will, by default, develop female sex organs if a masculinizing hormone does not activate to change this. This hormone is activated by the Sry gene found on the Y chromosome. This gene, however, does not only make changes to the body, but also to the brain.

Scientists have begun to study the brain’s connection to gender in order to better understand certain mental illnesses. For example, females are more likely to be diagnosed with major depressive disorder (MDD), while males are more likely to be diagnosed with attention deficit hyperactivity disorder (ADHD). What they’ve discovered is that the Sry gene, when activated in utero, sets off a hormone called androgen. This hormone is considered responsible for the feminization or masculinization of the brain, a process which happens during fetal development.

This is especially evident in people with intersex conditions involving androgen. One of these conditions, CAIS (complete androgen insensitivity syndrome), occurs in people with XY chromosomes. For some reason, as the name suggests, androgen does not affect them as it would most males. They still develop male gonads, but externally they appear female, and consistently identify as women. The same goes for people with CAH (congenital andrenal hyperplasia), who have XX chromosomes, but whose bodies make far more androgen than the typical female. These people, in the same way, undergo some degree of masculinization of the brain.

When it comes to brain shape and size, there are clearly quantifiable differences between male and female brains. Women have larger frontal cortexes as well as limbic cortexes. Men, on the other hand, have larger amygdala and parietal lobes. These cause many subtle differences in behaviour. This is why, on average, men and women are thought to act in certain ways.

The size and shape, however, are not the defining factor of a brain – neuron activity takes that title. A Penn Medicine study on brain connectivity discovered a major difference between male and female brains. It was found that females have greater connectivity between the two hemispheres of the brain, whereas males have greater connectivity within each hemisphere. In short, women’s neurons “communicate” back and forth between the left and right hemispheres, whereas men’s stay in their own hemispheres. The only exception was in the part of the brain responsible for motor control, where the opposite was observed.

This shows that women are more likely to connect the parts of the brain that are responsible for analyzation and intuition. On the other hand, men are more likely to connect those parts responsible for perception and coordinated action. This explains the results of several studies done in the past, where men and women were given the same tests. On certain tests, men consistently outperformed women, while on other tests it was the opposite.

This is enough evidence to suggest that gender is an ingrained part of our neurology. However, I would like to add that neurology is a complicated field. Every human’s brain is different, and there is nothing wrong with being a feminine man or a masculine woman; you are no less of a man or woman, if you are comfortable living as such.

This brings us to the topic of transgender people. Less than 1% of the population identifies as transgender, making it difficult to study, but some scientists have gathered enough transgender individuals to do substantial research. Brain scans have showed that white matter, the substance that connects the different part of the brain as discussed above, consistently correlates with the person’s gender identity and not their biological sex – even before they have medically transitioned in any way.

Transgender people are born with a mental illness known as gender dysphoria. Dysphoria is basically an extreme discomfort with one’s primary and secondary sex characteristics. It is usually treated by transitioning physically, which usually includes changing the secondary sex characteristics, and sometimes primary ones as well (although this involves an invasive surgery, so some people choose to opt out). If gender were a social construct, then no one would suffer from gender dysphoria. This is another point leading to gender being neurological.

Gender does not have to do with the clothes you wear, or the interests that you have. I could walk around in men’s clothing and fix cars all day, but that would not make me a man, because my neurology dictates otherwise. I think that most people who believe that gender is a social construct are thinking of gender roles, such as the clothing and interests that men and women are expected to have. But in my opinion, the real definition of gender is rooted in neurology.

As one final point, no discussion of gender is complete without one person asking about the validity of non-binary genders. I’m not going to go in-depth here, but I will say that I am open to the idea. I can understand how someone might feel non-binary; however, how would this translate to their neurology? Unfortunately, there are very few (if any at all) neurological studies on this topic, and none that I have been able to find. In the brain scans that I referenced earlier, certain people had brains with both masculine and feminine features. These people, however, all identified as male or female anyway. This is likely because, as some neurologists hypothesize, gender is primarily decided by neuron activity in the white matter. The size of other parts of the brain play a smaller part in gender. So, as it stands, I’ve never seen any proof of non-binary genders, nor have I seen any particularly persuasive arguments. However, I like to keep an open mind, and hopefully we will see some studies to prove or disprove the concept of non-binary. (And, before that happens, I will likely write an article going into more depth on my opinions!)

That’s all from me today, but I’d like everyone to remember: despite our neurological differences, everyone’s brain is based on the same structure. Translated from science-geek to English, that means that despite our differences, we are all human. Treat each other with kindness and respect. See you next time!



Hormones, Sexual Dimorphism, and the Brain

Sex Differences in the Brain – The Scientist Magazine

Brain Connectivity Study – Penn Medicine

Transgender Differences on Brain Scan – New Scientist