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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.

You said going through puberty is advantageous to brain development, something I never thought about but it seems obvious now that you said it, so I have a question. Does that mean kids put on puberty blockers will be less intelligent than kids who just go through normal puberty?

The more I read about this, the more I think these kids are so effed

Yes, there are studies done on girls who went on lupron for precocious puberty and their IQ dropped an average of 8 points if I remember correctly. Hormones aren't just cosmetic, people! We need them for many things.

Oh man. These poor kids. I was diagnosed with depression and anxiety as a kid and it makes me cringe to think of what would happen to me if I was born 10 years ago instead of 40 years ago

I completely agree--I wouldn't think there would be any difference at birth. I'm more referring to when people say that it's ridiculous for TIMs to claim to have a female brain because there is no such thing as a female brain... I've seen it again and again on here. It just strikes me as an odd claim from the GC folk.

It's not an odd claim because we do literally mean that no neurologist on the planet could look at a brain scan and know whether the brain belonged to a woman or a man.

The only way to reliably identify a brain as female is to check the biological sex of the person whose body it's in.

[–] ProxyMusic 12 points Edited

We all have female brains. But your female brain is different to my female brain, and both our female brains our different to Second Skin's female brain. Because brains are plastic, meaning throughout our lives they are shaped by our life experience, nutrition, hormones, metabolism, how much we use our brains, what we use them for - and by experiences like trauma, abuse, shock, happiness, bereavement, clinical depression, pregnancy, childbirth and maternity, aging, menopause, diseases of aging etc.

The human brain begins developing physically during gestation in utero and continues developing through childhood, adolescence and the first half of our 20s. The human brain doesn't reach physical maturity until we are 25/26.

TIMs think all girls and women have brains that make us pretty much the same - and that our brains are pink, small, delicate and not up to the rigors of logical, rational thought.

When TIMs say they have a female brain, they mean they what they believe is to be a female psyche - which is a psyche that likes the color pink, glitter and "girly" things. If they are tweens, teens or adults, it means that certain aspects of stereotypical sex bomb "femininity" gives them boners. TIMs think that a female brain/psyche = a male AGP brain/psyche.

BTW, I believe there probably are quite a few physical differences in male and female brain cells and some brain functioning - and that the more sophisticated research is done on cells and genetics, the clearer this will become. The sex hormone receptors in the brains of males and females, for example, appear to be different in nature, location, number and function. But as of yet, we don't know what the physical brain differences are, or how large and significant they are. Nor do we really know what, if any, real and lasting consequences they have in terms of brain functioning, processes, psychology and behavior.

So far, most of the physical brain differences found in the sexes have been small and subtle ones. Male and female brains are much more alike than they are different, and there is considerable overlap between the two sexes. Doctors and scientists can't tell the difference between a male brain from a female brain just by looking at its gross morphology.

I suspect that if and when more cell research finds physical sex differences in the brains of humans, those differences are gonna turn out to be very different than to the kinds of differences that have long been assumed to exist. I also think there will continue to be enormous variations in the brains from one woman to the next, and from one man to the next. I also think the human brain is so incredibly complex that it'll never be figured out fully.

[–] SecondSkin 6 points Edited

The female brain in an adult means either biologically female; so female chromosomes and hormones. Which a TiM can’t have (synthetic hormones are not hormones).

Or it means socially conditioned brain development, where there’s a difference. Which TiMs can’t have because they aren’t socialised as a woman. 🤷🏼‍♀️

So they can’t have a female brain.

[–] Dee 3 points

Men can't have "female brains" for the simple reason that they're not female. Being female, and having a brain, doesn't cause us to automatically want to conform to gender norms imposed on us by society. That's the gist of it, I guess.

Would it make a little more sense to think of how we might say 'there's no such thing as a female heart' (ie hearts pump blood, all hearts do this, to a greater or lesser degree depending on the health and fitness of the person it is in, the function and operation of the heart isn't appreciably different depending on the sex of the person, we can pretty much extrapolate how hearts work in humans from observing both male and female hearts, etc) and also, at the same time, any heart inside a female person is a female heart?

there's no such thing as a female heart' (ie hearts pump blood, all hearts do this, to a greater or lesser degree depending on the health and fitness of the person it is in, the function and operation of the heart isn't appreciably different depending on the sex of the person,

Actually, male and female human hearts are very different to one another in terms of structure and function. Male and female hearts do the same job overall, but the way they go about it is different.

While it is widely recognized that the female heart is smaller than the male heart, it has long been ignored that it also has a different microstructural architecture. This has severe implications on a multitude of cardiac parameters.

Here, we systematically review and compare geometric, functional, and structural parameters of female and male hearts, both in the healthy population and in athletes. Our study finds that, compared to the male heart, the female heart has a larger ejection fraction and beats at a faster rate but generates a smaller cardiac output. It has a lower blood pressure but produces universally larger contractile strains. Critically, allometric scaling, e.g., by lean body mass, reduces but does not completely eliminate the sex differences between female and male hearts.

Our results suggest that the sex differences in cardiac form and function are too complex to be ignored: the female heart is not just a small version of the male heart.

When using similar diagnostic criteria for female and male hearts, cardiac disease in women is frequently overlooked by routine exams, and it is diagnosed later and with more severe symptoms than in men. Clearly, there is an urgent need to better understand the female heart and design sex-specific diagnostic criteria that will allow us to diagnose cardiac disease in women equally as early, robustly, and reliably as in men.

https://www.frontiersin.org/articles/10.3389/fphys.2022.831179/full

Pretty much every organ and system of the human body that has been looked at to see if there are sex differences has turned out to have extensive and significant differences that aren't visible to the naked eye or just by looking at the gross morphology. Heart, liver, pancreas, kidneys, digestive tract, skeletal muscles, lungs, airway cells, respiratory system, immune function and response... and so on - they all are different in male and female humans

I think I hear what you're saying, but hearts actually do exhibit sexual dimorphism as well... True that functionally they are the same, but the differences might matter more when considering, for example, heart diseases I would think? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8189176/

[–] 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.