QuoteHowever I have slowly started to get the impression that the community view gender is an objective biological reality. Mostly in the form of seeing people cite studies showing some differences in MRI scans of transgender brain. This has confused me further, aren't these studies arguing the opposite of the general principle of being trans? That you're the gender you identity with, not the one determined by your biology? Individual brain variance is pretty high. If someone was assigned male at birth, then identified as female, but scans did not indicate a transgender brain would she not really be transgender?
It depends. Which part of your biology determines your gender? The bits between your legs? Some of the interesting bits in your brain? The dimensions of bones in your extremities? The exact chromosomes you have?
I'm one of these confusing people. I know what my gender identity is, but some bits of me don't match that identity. Some do. It is a puzzlement... Not!
In utero, around 10 weeks into my mother's pregnancy and my development, something interesting was introduced. In my particular case it was a chemical called diethylstilbesterone, or DES. This was given to Mom to try and avoid a miscarriage, as the drug was thought to be a good way to block that. Alas, 1950s biochemistry was a bit weak. The drug could and did cross the placental barrier, exposing me to around 500,000 times the level of estrogens that a modern birth control pill might do.
This is important, because it is ultimately the level of 'messenger proteins' that drives gender specific tissue differentiation in a developing fetus, not the presence or absence of a Y chromosome. In a boy, there's typically an X and a Y chromosome. The Y chromosome is a runt, with 6 active genes, including the srY gene. In a girl there's two X chromosomes and no srY gene. When the fetal cells are multiplying, they form a little sphere, then a tube of sorts. In that tube, the inside is exposed to different cell secretions than the outside, and some of those chemicals trigger tissue differentiation. Some cells become the ones that generate eggs or sperm, which one being determined by that srY gene being there or not. These cells also make messenger proteins, like estrogen or testosterone.
The rest of the tissue differentiation is driven by the ratios of these messenger proteins. Depending on which ones are dominant, different genes are activated, and proteins get folded differently to build our parts.
Up til somewhere around the 10th week of my development, I had messenger proteins that signaled the cells to build a boy. Stuff that would become the core of my body, including genetalia, were laid down by the genes so activated. When the DES entered the picture, different genes were activated, and the parts of my body being grown followed a slightly different set of blueprints. Bone lengths in my extremities were laid down a bit different from the boy plans (the 2D:4D ratio in hand finger lengths, for example). Layers of tissue atop my brain stem were built a bit differently (the bed nucleus of the stria terminalis, for example).
The result is a baby that looks mostly like a boy on the outside, but has a secret surprise hidden in the package. This is just one of the many paths that can lead to someone like us. Most of the answer lies within the central nervous system. (The stria terminalis, for example, is involved with basic movement, converting the impulse to move a limb, for example, into the graceful triggering of thousands of muscle impulses. Get the wrong model for your body, and you'll have gross motor skill coordination problems like I did.)
Bear in mind that much of the basic function of the brain, as laid down in fetal development, is part of the limbic system, which is very much a chemically driven system build around messenger proteins, not 'wiring' in the brain. Feed it the wrong chemicals, in ratios it doesn't expect, and there will be trouble. (Exactly my problem. Switch off the testosterone, add estrogen, and suddenly the levels of stress hormones generated by the limbic system dropped drastically.)
The causes appear to be biological, set in the prenatal environment. Do not assume that biology insists on a simple binary answer. That sort of simplification of reality is best left to fools, politicians, and others of their kind.
