Gender and the Brain
- Published19 Sep 2017
- Reviewed19 Sep 2017
- Source BrainFacts/SfN
Today, individuals are challenging the traditional gender binary and expressions of gender identity. Neuroimaging studies are shedding light on the brain differences between trans- and cis-gender individuals.
This video was produced for the 2017 Brain Awareness Video Contest.
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In our society, gender is being either male or female. However, in recent years, gender much like the accompanying gender roles - such as men at work and women in the kitchen, is beginning to change.
Contrary to popular belief, gender and sex are not the same thing. Gender pertains to more societal and cultural characteristics that define women and men. Sex is the physical or biological characteristics such as the reproductive organs. And in some individuals, these are conflicting. This is called gender dysphoria; when person’s gender identity doesn’t exactly line up with their biological sex.
When this happens, people often change or transition their outward appearance to express that of their true gender identity. These people are termed “transgender” or trans. A transsexual person is someone who has continued with this transition to the point of hormone therapy and sex reassignment surgery.
In most cases, a trans person is male to female, or female to male. Many people believe that the “gender dysphoric” diagnosis pathologizes trans individuals. In doing this it’s easy to disregard and invalidate these peoples’ realities. If we remember, not too long ago homosexuality was also considered a mental disorder. The American Psychiatric Association has stated that "gender nonconformity is not in itself a mental disorder”. Where it becomes pathological is in the presence of clinically significant distress associated with feeling like you’re in the wrong body.
As said before, many people believe that being trans is nothing more than a mental disorder or even a choice, but recent scientific evidence leads us to the brain! In recent neuroimaging studies, diffusion tensor imaging or DTI has shown to be sensitive in detecting white matter differences in the brain between sexes. One study found that the white matter tracts in the brain of female to male trans individuals is more similar to the brain of natural born males, than it is to natural born females. In other words, in females who identify as male, their white matter tracts are actually, naturally more male. This study also found that two brain areas involved in higher cognitive functions are already more masculinized in FtM trans people before they undergo hormone therapy. Again, their brain is naturally more male than female.
Another study looked at the white matter tracts of MtF trans people, and found that their brain is significantly different than both the male and female controls. These differences were primarily in regions involved in emotional processing, and movement. These researchers argue that, in these individuals (MtF) these areas are not simply more feminized, but have not been completely masculinized. Arguing that full masculinization did not occur during brain development, leading to white matter tracts that are halfway between male and female.
This can be further understood by looking at the mechanisms responsible for gender identity that occur during fetal development of the brain. While we’re in the womb, a testosterone surge masculinizes the brain, whereas an absence of this surge results in a feminine brain. Further, the sexual differentiation of genitals and the sexual differentiation of the brain occur separately and independently of one another, meaning that the degree of masculinization of the genitals may not reflect the degree of masculinization of the brain. -this is thought to result in the feeling of being in the wrong body.
As we can see, there is strong scientific evidence showing that expressions of gender identity occur naturally, and that they pose no threat to society. It isn’t an illness or a choice. This programmed gender identity is irreversible, and sometimes isn’t as easy as being just male or female.