You Don't Have A Female Brain In Your Male Body

Added: 2026-05-13

[00:00:00]It turns out that the precursor genitals transform into either female or male during the first trimester of pregnancy.

[00:00:07]The precursor brains on the other hand transform into female or male during the second trimester of pregnancy.

[00:00:14]So the current working model is that a unique mix in my mom's womb caused the precursor genitals to transform one way but the precursor brains to transform the other way. The latest research is showing that female and male brains do develop differently in the womb, possibly giving us females this innate sense of being a woman. You don't have a female brain in your male body.

[00:00:41]That lets me cancel for transphobia for the 50th time this year. But let's get into it anyway.

[00:00:47]>> A person's gender identity is determined long before they are born. Your gender is determined by your brain, not your genitalia. I think the idea that a transgender person might have a female brain in a male body or vice versa just feels right. You know, to me, gender dysphoria really just means unhappiness with one sex. But often it goes further than that, as if he was supposed to have been born the other sex. These feelings are incredibly hard to describe or rationalize to another person. I'd wager very few trans people have a concrete idea on why they feel this way or where these feelings came from.

[00:01:20]So the instinct is it's probably innate and it's probably found in the brain. It would be incredibly legitimizing if something so divisive if a definitive physical marker was found consistently in trans people explaining the feeling of consciousness as the other sex to which you are. After all, questions about trans rights are going to have to progress past whether trans even exists at all beyond delusions or social contagions or whatever. If you can point to something physical, observable, and consistent. Gender is determined biologically. It is simply that again, gender is not determined merely by the sex chromosomes and is an incredibly complex neurochemical phenomenon. You had a roughly 50/50 chance of being born either sex. Could something have happened during your development in the womb to where your brain developed differently to your body? It remains a theory without a clear answer either way. But absent of any more solid conclusions on why people are trans, variations on the idea of there being some kind of neurobiological basis to being trans persist. Out of the gates, I would concede that female brain, male body, or vice versa is probably an extreme version of this idea, but it's a good starting point. For this idea to make sense, female and male brains need to exist as distinct from each other in the first place. It's going to get complicated incredibly quickly.

[00:02:36]What you see is, you know, you got somebody who is, you know, Pepsi flavored sex according to their chromosomes and gonads and hormones and genitals and everything else, but who nonetheless has always been saying, "I don't feel like Pepsi. I feel like Coke." And you look in their brain, and in some of those areas, it's more like Coke.

[00:03:00]>> The one constant observation throughout history has been that men have generally larger brains than women. which shouldn't be too surprising when men generally are larger. In the 19th century, craniology was used to infer male superiority, whilst early psychology treated women as the lesser by default. While Samuel George Morton used skull size to denote intellectual ability between races with Caucasians coming out on top of course. Gustav Labon, disciple of Paul Broker and who invented a pocket cranometer to measure the skulls of people he met on his travels, was published in 1879, stating, "In the most intelligent races, as among the Parisians, there are a large number of women whose brains are closer in size to those of gorillas than to the most developed male brains. This inferiority is so obvious that no one can contest it for a moment. Only its degree is worth discussion. All psychologists who have studied the intelligence of women as well as poets and novelists recognize today that they represent the most inferior forms of human evolution and that they are closer to children and savages than to an adult civilized man.

[00:04:04]They excel in fickleness, inconsistency, absence of thought and logic and incapacity to reason. Without doubt, there exists some distinguished women very superior to the average man. But they are as exceptional as the birth of any monstrosity. as for example of a gorilla with two heads. Consequently, we may neglect them entirely.

[00:04:24]Meanwhile, in George TWW's article, The Psychology of Woman, published in Popular Science Monthly in 1895, although presenting an overall more balanced and nuanced account of the psychological differences between women and men, still refers to women as infantile and possessing traits found in primitive races, whatever that means.

[00:04:44]Whilst their dress sense provides much confirmation of the theory of woman's arrested or development, times changed, technology moved on, the science evolved, but some attitudes remain the same.

[00:04:56]>> The reason why trans women are women, I in my view is that they have this neurobiological underpinning that predisposes them to being woman. As Anne Fosto Sterling wrote in Sexing the Body, an observed but disputed belief that women have wider corpus colossums became big news in 1992, generating speculation in media articles that this could explain why girls are less apt than boys to gravitate towards fields like physics and engineering, and that these findings discredited some feminist ideologues who assert that all minds are created equal and women would be just as good at math if they weren't discouraged in school.

[00:05:32]Meanwhile, in Lee's Aliotal's comprehensive synthesis of brain studies dumped the dimorphism, some studies found either no significant difference in corpus colossum size between males and females or actually found it to be larger in males. Five of the six largest studies found no difference by sex.

[00:05:50]Finally, how measurable these differences even are is also questioned by Fausto Sterling who wrote, "One could imagine the Corpus Colossum as a bunch of transatlantic telephone cables in the middle of the Atlantic. The cables are bundled at its connecting ends. The corpus colossum loses its structural definition, merging into the architecture of the cerebrum itself. The real corpus colossum, then is a structure that is difficult to separate from the rest of the brain. We'll get into a few more examples of parts of the brain later, but you get an idea of how brain differences between men and women have historically been used to push regressive stereotypes and gender roles, even when the difference might be meaningless or disputed as to whether it's even there. So, we're not exactly off to the best of starts. And when asserting sexbased brain differences, it is important to make sure it's not starting from a place of this is why one sex is better than the other. Edgy, 1800 cranologist be damned. These days, girls consistently outperform boys in education. It doesn't seem to me like outdated stereotypes and gender roles are of very much help when actually arriving as close to the truth as we can. The best we can say for sure is that female and male brains are little else but two averages in overall size with a lot of overlap divided into overall parts of the brain which also manifest two averages in size with a lot of overlap. All of which correlates pretty well with men and women's average overall body sizes in the first place.

[00:07:12]What we get then are studies reporting various combinations of various parts of the brain being larger in men, women, or neither with little ability to infer what this actually means and with past efforts to infer anyway, often leaning on patriarchal ideals that don't seem to hold up today.

[00:07:28]Individual brains, when matched to these averages, present as mosaics where some parts are larger and some are smaller.

[00:07:34]So, if your brain has some parts that more line up with the male average size and some that more line up with the female average size, which type of brain do you have? See, there's a huge confounding factor. Brains are very plastic. Your brain looks different depending on what time of day it is, how hydrated you are, what kind of job you have, what activities you partake in, the experiences you've had in life up until now, and much more. There's a famous study by professor Elellanena Maguire which found London bus and taxi drivers to have greater volume in the posterior hippocampus and a follow-up found greater gray matter in the mid-posterior hippocampi.

[00:08:10]Your brain constantly adapts to your environment condition and experiences and its physical form reflects this. So even if genetic sex gives some predispositions to brain structure, how the brain actually develops and what it becomes are affected by a wealth of factors.

[00:08:24]So, what does this mean for trans people? Well, you can't really have a female brain and a male body if male and female brains aren't really a thing. But you also don't really have a male brain either in that case. So, I suppose we're back to where we started. The wrong brain for your body line works as metaphor to try and explain what it feels like to be trans, but doesn't have much validity beyond that. So, then usually when arguing, there's a neurobiological basis to being trans.

[00:08:48]The argument isn't trans people have the wrong brain for their body. It's closer to trans people have a unique brain phenotype compared to men and women or that specific parts of the brain differ in trans people in a way that more resembles the other sex and this might be the source of their trans identity.

[00:09:03]Several studies have shown that transgender brains are both structurally and functionally more similar to their experienced gender identity than their biological sex.

[00:09:13]>> This isn't completely unfounded, but once again, it's complicated.

[00:09:16]>> In simple terms, most cases of gender dysphoria work like this. One may be born with one biological sex, but their brain is more like the opposite sex.

[00:09:25]>> When physical differences are observed in studies between trans and cis people's brains, generally it's specific parts of the brain that are differently sized on average in the trans cohort than the cis cohort, suggesting said areas of trans women's and men's brains are therefore feminized and masculineized, respectively.

[00:09:42]An example is Zubior Alozza Ital where 24 untreated trans women were found to have higher thus feminized cortical thickness than the control group of 29 men when their brains were scanned. It was asserted in this study that previous studies had established a pattern of higher cortical thickness in women than men. However, much like the corpus colossum, Le Elliot challenged this in dump the dimmorphism, finding some studies observed thicker cortices than men, some in women, and some showed negligible difference. Elliot found MRI scans were more likely to find either no difference or greater thickness in women, whereas postmortem hisystologology, which provides higher resolution data, leans towards greater thickness in men. This means whether or not the greater cortical thickness found in trans women is a feminized effect is debatable. You probably also notice the tiny sample size of this study. This will be a theme here. As you might expect, the smaller the sample size, the less generalizable the findings are. As you may well scan another 24 brains and find a completely different pattern because there are 8 billion of us and brains are highly individualized.

[00:10:47]Finally, Spency Mueller's mega analysis, which we'll cover in more detail shortly, didn't find a sex atypical pattern in the cortical thickness of their trans cohort compared to the cis control cohort. One study found that trans women who, despite being assigned male at birth, had a smaller female-sized structure in the hypothalamus. MRI scans also show the brain structures of trans people to be more similar in thickness to their experienced gender and not their sex.

[00:11:12]Delving deeper, we have two parts of the brain that have consistently been observed to be larger in men than women.

[00:11:18]The INAH3 or interstitial nuclei of the anterior hypothalammus 3 involved in regulating sexual behavior and the BNST or bed nucleus of the strieris associated with stress and fear responses among other things. These areas have both also been observed to be smaller in trans women than men. Alicia Garcia Falggeras and Dick Swab published findings in a publication called Brain regarding the INAH3 in 2008. Postmortm brain material was used from 42 subjects, 14 control males, 11 control females, 11 maleto-female transsexual people, one female to-male transsexual subject and five non-transsexual subjects who were castrated because of prostate cancer.

[00:12:04]We showed for the first time the inahh3 volume and number of neurons of male to female transsexual people is similar to that of control females. The female to male transsexual subject had an INAH3 volume and number of neurons within the male control range even though treatment with testosterone had been stopped 3 years before death. The castrated men had an INAH3 volume and neuron number that was intermediate between males and females. Unfortunately, this is the only source I can find for this particular difference. So presumably, it's never been replicated. Moreover, a similar difference between trans women's and men's INAH3 has been observed between gay and straight men. For example, in 1991, Simon Ly found inahh3 was more than twice as large in heterosexual men as in the women. It was also, however, more than twice as large in the heterosexual men as the homosexual men.

[00:12:58]Meanwhile, the BNST was observed by Xiao in 1995 to be far smaller in six trans women than in cis male controls, seemingly unaffected by sexual orientation, but mostly post hormone replacement therapy. Once again, this is the only study I can find on this.

[00:13:14]Although Croa Ital used the same cohort to assert that male to female transsexuals have female neuron numbers in a limbic nucleus which appears to also refer to the BNST with female neuron numbers meaning fewer even though there isn't really a binary male or female number of neurons. Again there's a pattern where brain structure is assumed to be sexually dimorphic. The BNST is another part of the brain where sex difference is disputed as per barrieral in 2024 whose findings suggested no significant effect of sex and that total brain volume showed a positive relationship with BNST volume.

[00:13:50]Results of the model without total brain volume showed that removing this variable led to sex becoming a significant predictor of BNST volume and ultimately called for caution when reporting evidence of BNST sexual dimmorphism.

[00:14:03]It sort of feels like we could do this all day, right? There are studies that found small numbers of trans women as fitting a little better into the female average to the male average in terms of size of some part of the brain or neuron count or certain types of brain matter activity. But that these averages exist the way they do for the most part conforms with men having slightly larger brains than women on average, which conforms with men being slightly larger in general than women on average.

[00:14:29]You'd think we'd have learned by now to be wary of placing too much importance on size when, as recounted in the gendered brain by Gina Ripen. Researcher Alice Lee found when measuring skull volumes of leading anatomists as well as female students in 1898, one of the most eminent of these anatomists had one of the smallest heads and indeed that one of her future examiners as Sir William Turner was eight from the bottom. The discovery that these eminent men's heads were on the smaller side magically created a large number of instant converts to the conclusion that linking skull capacity to intelligence was obviously ludicrous, especially as some of the Bedford students had greater cranial capacities than the anatomists.

[00:15:07]Granted, we've moved away from asserting differences in intelligence. So, what are we measuring instead when looking for differences in a transerson's brain relative to their sex and identified gender? how valid their identity is based on two sizes of an organ that isn't used to differentiate sex in the first place.

[00:15:24]>> Transgender people tend to have the brain structure that confirms their identity that they identify with.

[00:15:30]>> If you're a trans woman and you have your brain scanned and it's about as typically male as a brain is possible to be by the kind of metrics used in these studies to determine trans women have feminized brains, would that honestly change your perspective over your gender? If you're a sis man, would you seriously consider transitioning gender for the first time if you found out your brain leaned towards the feminine average? Probably not.

[00:15:52]So when AI models are used to predict brain sex and establish a pattern of 24 trans women's brains fitting more of an identified gender average than a sexypical average as in Keratal's study from 2022 brain sex in transgender women is shifted towards gender identity. A sensationalism that makes me wonder how often these researchers exaggerate in order to not fall prey to publication bias. How much is AI bias by adherence to a sex binary built in by its human creators where that binary seems almost entirely irrelevant to what it's studying? The results were that trans women were more female than cis males but significantly less female than cis females. However, the violin graph provided whilst initially appearing to support this conclusion actually shows that the male cohort is skewed towards the male end of the y-axis by an exceptional result. And without that, there's little difference shown between cis men and trans women using what is already a questionable metric in the first place.

[00:16:50]>> This was a paper again that was touted as showing that that that uh trans male transgender women have um a complete a unique brain set. But if you look at this, they are a subset of the males.

[00:17:05]>> But we saved the best till last. In 2021, Sveny Mueller Atal published findings from a mega analysis from the Enigma transgender person's working group. This study acknowledges the inconsistent results of previous studies using MRI data to establish a link between various parts of someone's brain and their trans status. They're often binary approach treating male and female as a spectrum of sorts and the small sample sizes. Although this particular study only incorporates data from around 800 people, roughly half of whom were transmen and women, we still have questions over how generalizable any result here would be. The study found that the brains of trans people had various unique patterns compared to the brains of men and women, expressing this as trans people having a unique brain phenotype. This is probably a better approach than trying to match the sizes of tiny parts of the brain to an average that resembles the gender transition to.

[00:17:57]But brains are highly individualized already. The study can't really speak to what function any of these differences have that might inform the person's gender identity away from their sex. And when presented in graphs, we do fall back on the binary model, putting men and women at opposite ends of the spectrum with huge amounts of crossover and treating it as a substantial finding when some trans people land somewhere in the middle. But let's look at the graphs, which each represent the volume and/or service area of various parts of the brain, which bear in mind generally very small, and the actual differences in size for each are even smaller. From left to right on each graph, you have cis men, cis women, transmen, trans women. In general, what we're seeing is that cis men have the largest of each brain region. Trans women are smaller.

[00:18:40]Then cis women and trans men are both smaller again with little distinguishing them. One issue that comes up right away for me looking at this is that we treat gender identity as something that works the same way in both sexes, let alone any two individuals. If these patterns are supposed to indicate that gender identity manifests physically in the brain structure, why do trans men's brains show as so similar to cis women's brains, would it make sense that male people or trans women have a so-called brain phenotype that reflects their gender identity and trans men don't? And whilst the idea of a unique brain phenotype for trans people suggests a validity to trans identity as something originating innately in the brain, it also throws up its own implications that should give us pause for thought. If trans people have a particular brain phenotype and brain scans are routinely used before any medical transition steps are taken, what happens when someone without the phenotype shows up asking for gender affirming care, reporting gender dysphoria? Would that person be dissuaded or refused care because their brain doesn't look trans enough? What might happen if this logic becomes more widely adopted and we found that this brain phenotype showed in the womb? I think ultimately coining additional brain phenotypes within the already questionable male and female phenotypes just amounts to coining additional averages within the averages which all overlap to a large degree so are only of so much use to begin with. The trans phenotypes are based on the sex phenotypes just with self-reported gender identity added into the mix.

[00:20:06]Something which is illdefined means something different to every person, can change based on a lot of different factors, including social and environmental, and so is already a weak metric to base a brain phenotype on, and also retains all the issues with coining sex-based brain phenotypes. As discussed, >> scientists use MRI techniques to scan the brains of 18 people who were assigned female but identify as male and 24 male and 19 female heterosexual controls. The researchers found that the white matter of female to-male individuals who received no hormone therapy more closely resembled brains of the male subjects than the female subjects. It strikes me that you could probably follow a similar line of logic to coin brain phenotypes based on sexuality, seeing as how differences in the size of the INAH3 of homosexuals compared to heterosexual people have been observed, as well as there being a correlation with fractional and isotropy values that measure the integrity of white matter as found by Sarah Burkatal in 2017 to the point where adding in sexuality as a variable meant that trans people's fractional and isotropy values followed sex patterns in almost all cases. But what would be the point? And finally, what's there are some differences in the sizes of parts of the brain found between trans women and cis men in this study suggesting a link to some expression of transness in a male person's neurobiology?

[00:21:21]We're not given any indication as to why this link exists. Why would any particular part of the brain being a different size cause some male people to be more likely to transition?

[00:21:30]Neuroscience is limited in this way. We can see what size different parts of the brain are, but often we don't know why this is the case. We can see neuron activity but not what it means.

[00:21:41]>> And what we what you what we found is is in a majority of people who are trans eg if you're trans woman when their brains have been scanned.

[00:21:55]They've shown the markers indicating a female brain. To be clear, based on what I've covered here, it's not really fair to say there conclusively is not a neurobiological basis for being trans.

[00:22:08]However, we lack compelling evidence to say with certainty that there is. The idea that trans people develop differently between their brain and the rest of them in the womb has never been substantiated. The idea that there is a transbrain phenotype is poorly evidence at best and is based on the poorly evidenced idea that male and female brain phenotypes exist in the first place. Whilst there are potential political gains to be made improving transness manifests physically in the brain, the implications could also lead to unfair gatekeeping of treatment or even eugenics if taken to enough of an extreme. It would seem that organizations such as WP path, whose guidelines on trans healthcare are followed by many countries across the world for better or worse, would agree with me, as nowhere in their guidelines does it suggest a person seeking gender affirming care should get their brain scanned. And think about it. If you were experiencing gender dysphoria, would seeing what your brain looks like inform your decision whether or not to transition? If you were already trans, would it in any way motivate you to dransition if you saw your brain and discovered it was very sexypical?

[00:23:08]>> Sure.

[00:23:08]>> What about the neurobiologists?

[00:23:12]>> What about them? All you >> Yeah, the neurobiologists acknowledge the difference between trans people.

[00:23:16]They understand that that exists.

[00:23:19]>> What we're seeing is some effort to legitimize trans using science. If the trans brain is a thing, you can prove to skeptical lawmakers and voters that trans rights should be taken seriously.

[00:23:29]But this is a fool's errand. Gay rights concerns like samesex marriage show widespread support based on polls in countries like the UK and the USA, even though we've never found an innate biological source for homosexuality. Gay people have become more accepted in society regardless, and the hope is that trans people will eventually experience the same. Imagine we could conclude with certainty that there is no neurobiological cause of being trans and that to be trans is not an innate trait of a person. Would it matter? Would it stop people from transitioning anyway?

[00:23:58]Would it mean that what we call trans doesn't exist? I don't think so. So once again, I question what the use of any of this data is beyond curiosity.

[00:24:07]I don't think trans is something that needs legitimizing in this way in the first place. Trans people exist whether or not there's something in the brain that made them that way. If to a trans person, genetic sex itself isn't destiny, but it doesn't make much sense why brain structure would be either.

[00:24:22]With all that said, the neurobiological basis of trans is still a popular talking point. What I would like to say to those who make protrans arguments using these brain studies is to re-evaluate the evidence you're basing your belief in. Consider issues with sample sizes and replication. Consider what else could have influenced the results found. Consider whether a negligible or modest effect is being trumped up either because the researchers are invested in a particular outcome or because of publication bias where research finding substantial positive results is more likely to be published. Consider the overall implications of coining brain phenotypes in this way and whether the logical conclusion of this research is a good thing for trans people.

[00:25:01]And maybe one day a more substantial link will be found between transgenderism and a particular part of the brain. I doubt this is going to be found by insisting on sexing the human brain and seeing how trans people compare. I think a new approach would be needed. But to me, it doesn't matter either way. A trans person is not a brain in a jar, nor a slave to their neurobiology. No one is. Thanks for watching.