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I need to bring up something that's been bugging me.

We talk all the time about how sex isn't just genitals, it's every piece of our being. If you look into it, even our non-sexual organs are genetically dimorphic between men and women.

The inconsistency to me though is when we say there's no such thing as a female brain. All of a sudden, all of the femaleness that is intrinsic to every other part of who we are becomes invisible. I understand that we don't want to lend credibility to the idea that TIMs can have a "female brain," but even the research that exhibits sexual dimorphism in brains doesn't show that--in fact, while "trans brains" are mildly shifted towards their "preferred gender," they are still well-within normal ranges for their sex, and still outside the average range for their "identity." It's not a gotcha, and I don't think we need to be afraid of it.

The graphic on this study (under Results) is especially good to look at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8955456/

If anything, I think admitting that female brains do exist (with some variance within the sex, of course) and that TIMs do not have them is perfectly good evidence for being gender critical. (And for those who criticize lesbians for not sleeping with TIMs because we're genital fetishists, well, no, the brain plays a part too. Suck on that, "hearts, not parts.")

Some might call it sexist to say there are differences between male and female brains, but I think the it's more that the sexist conclusions that people come to as a result of the difference existing are problematic--ie: because "female brains" exist, women must be more predisposed to doing housework, or some other nonsense.

Also, when we talk about puberty blockers being harmful because of the importance of sex hormones in adolescent brain development, I think it's a bit willfully ignorant to not assume that estrogen and testosterone might have different effects on the brain.

Prove me wrong, please, or give me another way to think about it! I just think it's something worth tackling head on, rather than brushing aside.

I need to bring up something that's been bugging me. We talk all the time about how sex isn't just genitals, it's every piece of our being. If you look into it, even our non-sexual organs are genetically dimorphic between men and women. The inconsistency to me though is when we say there's no such thing as a female brain. All of a sudden, all of the femaleness that is intrinsic to every other part of who we are becomes invisible. I understand that we don't want to lend credibility to the idea that TIMs can have a "female brain," but even the research that exhibits sexual dimorphism in brains *doesn't show that*--in fact, while "trans brains" are mildly shifted towards their "preferred gender," they are still well-within normal ranges for their sex, and still outside the average range for their "identity." It's not a gotcha, and I don't think we need to be afraid of it. The graphic on this study (under Results) is especially good to look at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8955456/ If anything, I think admitting that female brains do exist (with some variance within the sex, of course) and that TIMs do not have them is perfectly good evidence *for* being gender critical. (And for those who criticize lesbians for not sleeping with TIMs because we're genital fetishists, well, no, the brain plays a part too. Suck on that, "hearts, not parts.") Some might call it sexist to say there are differences between male and female brains, but I think the it's more that the sexist conclusions that people come to as a result of the difference existing are problematic--ie: because "female brains" exist, women must be more predisposed to doing housework, or some other nonsense. Also, when we talk about puberty blockers being harmful because of the importance of sex hormones in adolescent brain development, I think it's a bit willfully ignorant to not assume that estrogen and testosterone might have different effects on the brain. Prove me wrong, please, or give me another way to think about it! I just think it's something worth tackling head on, rather than brushing aside.

43 comments

[–] SecondSkin 29 points Edited

There are female brains: the brains in female bodies are female brains. They have female chromosomes in all their cells and female hormones in them.

Vice versa for male brains.

At birth female and male brains are not functionally different.

Brain development is use dependent. Tell girls they are good at listening and caring then they practice these skills and their brains develop the neurological connections in these areas.

Tell boys they are good at being adventurous and math and they practice these skills and develop neurological connections in these areas.

The variation in older male and female brains are the result of this socialisation that conditions our brains.

That doesn’t change the fact that at birth female and male brains have no functional differences.

*edit to say: hormones influence at puberty is complex. We know that going through the normal puberty for the sex of the body is advantageous for brain development. Female versus male hormones are more complex than oestrogen versus testosterone. There’s no way of having a control to show that female hormones have a very different impact than male hormones on brain development. The huge wealth of research of adult brains show that there’s more difference within male brains and more differences within female brain development than there is between them, and a large overlap between them. If o versus t had some drastic different impact then we would see male brains be very different from female ones. And that’s not what’s seen in the research. Our bodies being prevented from going though the normal human development that they are designed to go through limits brain development. That might be fully reversible, it might not. Using pbs followed by wrong sex synthetic hormones might cause same brain development. It might not. There’s no way of establishing either without experimenting on children. And collecting data on children who are being groomed by predators and then have adults pander to their threats of suicide and demands for medicalisation, won’t give valid results either, because brain development is use dependent and so their brains will develop the neural pathways to threaten and manipulate and believe lies, not to think critically and develop negotiation skills and inter personal relationships skills.

[–] ProxyMusic 2 points Edited

At birth female and male brains are not functionally different.

But my understanding is that we don't really know for certain if the brains of male and female babies are indeed not functionally different at birth. How exactly would you test brain function in newborns to see if there are any sex differences?

Dr Lise Eliot is the expert in this field. She had the largest studies of sexed brain functionality. Iirc these use neural imaging and so on. It’s a long time since I’ve studied her original work (or feels like it anyways) but it was generally accepted as sound when we evaluated it in class and her work is widely accepted, published in peer review journals, evidence based.

[–] ProxyMusic 1 points Edited

She had the largest studies of sexed brain functionality. Iirc these use neural imaging and so on.

But did she do really do her research on newborns? I am taking issue with the claim that we know for certain that "at birth female and male brains are not functionally different."

I'm willing to believe this, but I still don't see how that would be possible to come up with practical, accurate ways to test newborns for differences in brain function so that we know for sure. Newborns cry, sleep, eat, poop, wee, cuddle/snuggle and suckle. They can startle and feel pain, but they can't even see or make out colors yet. They can't hold their heads up yet, or turn their heads in the direct of a sound. How exactly did/would anyone measure neonates' brain functionality?

I see such research as having ethical roadblocks too. I also can't imagine mothers/parents volunteering their healthy newborns to get brain imaging.

I just looked up Eliot's work, and see she published a paper in 2021 which is a review of all the research in this area. She says:

studies of infants and children are rarer and generally much smaller than studies of adults.

Also, all the studies she references on infants and children - and in her work and the work of others she looks at - is solely focused on gross morphology such as total brain size/volume or structure, structure, segmentation, and the relative size of different parts of the brain. AFAICT, the research doesn't look at brain function at. Nor does it look at brain structures, tissues or cells at the microscopic level.

https://www.sciencedirect.com/science/article/pii/S0149763421000804

Brain imaging strikes me as a pretty blunt instrument. It can detect brain structures and some kinds of imaging done in certain ways can detect brain activity. But brain imaging can't detect microscopic tissue and cell differences - and my hunch is that the differences in male and female brains will turn out be microscopic ones at cellular and genetic level.

I see Eliot has a couple book out about brain differences in children, which I have just ordered. Thanks for mentioning her. I've been meaning to read these books for years.