Are the male and female brains different?

I’ve heard the explanation of transgenderism as a “male brain in a female body” or vice versa.

Now, I’m not knocking transgenderism. If you feel like you’re a woman and want to be treated as such, okay, whatever. My question is about this specific explanation. Because by our current understanding of neuroscience, it’s wrong, isn’t it? As far as I know, the male and female brains are the same. Women (as a generalized group) and men (as a generalized group) do behave differently, but I thought that was mainly attributed to differences in hormones like testosterone.

Am I wrong? Is the actual anatomy of the brain different for men than it is for women? If so, how?

Disclaimer: This is a QUESTION. It is not an argument, not an attempt to attack or disprove or anything. I tried to word it as such, please in turn try to read it as such.

The male and female brains have very large differences actually. The proportions of white and grey matter varies by as much as a factor of 10 or more, and they are wired together quite differently. Brains scans show that male and female brains perform the same tasks very differently.

For transgendered people specifically it’s not so much a matter of a fully “male brain in a female body or vice versa”, as it is certain* specific* areas of the brain that are apparently vital to gender identity being misgendered.

See this:

Interesting take and unintendedly good experiment. Basically they took an otherwise healthy fully formed baby boy and removed his damaged genitals and surgically transformed him into a girl. The doctor subscribed to the “blank slate” theory. The outcome was that the subject was very obviously psychologically male despite lack of glands producing male hormones since birth… but then, in today’s (somewhat) more tolerant era we se this concept all the time with transgendered individuals.

I guess a more specific question is - are there specific physical differences that are visible or determined by tests? Good question…Idunno.

Yes kind’a sort’a explain later: the corpus callosum (the part which joins both halves of the brain) is thicker in women, and there are also differences in MRI. Links to more references. All references are from the same publication.

The “kind’a sort’a” is because with these things one always needs to keep in mind that the differences refer to averages, and that someone being an outlier for their gender (or whatever other classification is being used) can put them in values which would be more normal for the other class, without necessarily moving them to this other class. IOW, a woman might have a relatively-thin corpus callosum and that by itself doesn’t make her a man any more than being 190cm tall does.

This explanation is powerful and accessible as a way of noting how brains are gendered, as well as explaining what being transgender is all about.

And some people who are transgender say, yes, this is exactly it. However, there are many people who are transgender who say that this is not what it’s about, or that this is partly correct but partly wrong.

I also get the sense that some people feel their own brains as being strongly gendered, whereas others feel they are less strongly gendered (I myself lean somewhat toward “less gendered” in this subjective and imprecise sentiment).

There are two books by the same author, “The Female Brain” and its followup “The Male Brain” that are all about brain gender and differences. Now, they have been strongly criticized for making too definite and neat a case, but the criticism has focused more on the author’s statements about which physical regions of the brain serve what functions. Less of the criticism is about the argument that the two physical sexes have somewhat different typical functioning.

Okay, thanks for the explanation. I didn’t know there had even been enough research done to know that certain specific areas of the brain are vital to gender identity.

I’ve read that book, but I’d forgotten that they actually removed his testicles, which would severely reduce his testosterone levels. I’ve also heard of some intersex cases where people with ambiguous genitalia are made to appear female but identify as male. Which of course then leads to the question of if you’re born with ambiguous genitalia, are you also born with an “ambiguous” brain?

Thanks for the links, they look substantial while still being understood by the average reader who doesn’t have a background in neuroscience – those can be hard to come by!

That’s linked in part to culture, including family/school/class culture. If you’ve grown being told that your groin doesn’t define which professions you can choose, encountering notions such as “nurses are always female” and “girls can’t be engineers” is absurd because it links two things that in the system of values you were taught and have absorbed as normal, aren’t linked. If you’ve grown up being told left and right that “nurses are always female” and “girls can’t be engineers”, you’re likely to end up freaking out at the sight of a bearded nurse.

Those differences in gender perception are linked to gender being a sociological concept; one of the issues that blurry these kinds of discussions is that the use of “gender” to avoid saying “sex” helps confuse the issue.

So, unfortunately I don’t have a source for this, since I can’t remember the context in which I heard this. But I heard an expert in this field talking about this, and she said that although there are many, many studies claiming to have found significant physical differences between male and female brains, meta-studies reveal that so far, none of these reported differences have been consistently replicated in other studies. I think the jury’s still out on the actual science.

Of course male and female brains are different. In size if nothing else, but actually as mentioned, there are other differences. The real question you have is do transgendered people have different brains than their biological gender and the answer is… yes. Though they don’t have brains that resemble their expressed gender either. I’m not sure it’s even fair to say that they have a mix of brain features. They are their own thing. Of course, there is a great deal of variability among brains and there are women who say they are women and behave in every way like a woman (whatever that is supposed to look like), but have thin subcortical areas like a man. I think that a good way to look at it would be like height. If you asked are there differences between men and women’s height, of course there are. It would be ludicrous to say that there isn’t, at the same time, being 6’2" as a woman doesn’t make you a man or masculine, it just makes you tall. Another thing to realize is that we don’t know why there are differences in brain structure between men and women. It might be genetic, or it could be environment. Getting back to height, the average Indian male is shorter than the average German female. If you look at Indian-Americans though, males are much taller than German females. Nutrition and diet account for the difference. In a similar way, are we seeing brain differences among transgendered people because of some sort of genetic tinkering or is it environmental, perhaps they spend more time around girls as children and girls as a whole are doing some activity that results in a different brain structure from boys. It’s hard to say.

No, that wasn’t my real question. My question is if male and female brains were different, and if so, how. It is *inspired * by comments re the brain of a transgender person, but the actual question I’m asking is strictly about the difference between a male brain and a female brain.

The answer is still yes.

-They are different sizes on average.
-The right half of the ventromedial prefrontal cortex of men is more active than in women
-Women have more grey matter and cortical thickness than men and distribution of grey matter is different.
-The anterior cinculate cortex is smaller in boys
-the neural connections between and within hemispheres are different.
-the left side of the hippocampus is more dominant in women and the right side is more dominant in men

Very, very simplistically, if you stereotype men and women behaviour, lots of it is coming from brain differences. Men are wired to more efficiently process coordination and perception while women process intuition and analysis better. Men have decreased activity and brain volumes in areas of the brain relating to aggression. They have increased activity in areas relating to emotional control.

If you’re an evolutionary psychologist, you might say- again very simplistically and acknowledging that it’s not completely clear-cut and reduced activity or size in a particular area of the brain does not mean there is no activity in that area - that, “Men’s brains are designed to be aggressive and put a spear through a sternum. Women’s brains are designed to create social cohesion.”

Perhaps 20 years ago I went to a speech given by a University of Chicago neurologist who studied this very thing. Her method was to compare men and women who had identical traumatic brain injuries and see if they were any different.

Turns out they were and in some interesting ways too. For instance (the one example I remember) she showed a man and woman with the same brain injury a drawing of a triangle whose sides were composed of the letter “Z” repeated (each line was a string of the letter “Z”). They were each asked to draw what they saw.

The man drew a triangle but with lines and no letters.

The woman drew three parallel lines of the letter “Z” but not the shape of the triangle.

If they show that image to one singular man an one singular woman, then that’s not much of a study.

Yeah. That’s like me saying “Women are vegetarians, men eat meat” based on my own marriage. Albeit easier to refute than this brain injury anecdote.

It is just the one anecdote I remember. She had many more examples and of course her pool of subjects and years of study was larger than the anecdotes she shared with us in a 45 minute, casual dinner setting.

I think it is probably a safe bet that a University of Chicago researcher knows how to properly go about a medical study. That university would not have much tolerance for a charlatan doing pseudo-science.

Why that is not obvious to you I have no idea since I noted it was “the one example I remember”.

You would be surprised

Research fraud is extremely common. There are perverse incentives to cheat and they are amplified at prestigious institutions. The Lancet actually had an article that claimed as much as half of all scientific literature is false. Most of what they cover is misinterpreting statistical anomalies, but also includes simply making up numbers to advance preconceptions. You have a system rigged toward demanding you produce publications and turn them into grants. Let’s say that you’re working on a paper and the numbers come out iffy. Announcing a finding of ‘we’re not sure’ doesn’t generate much interest from grant-giving agencies. Nudging those numbers just a tad can be the difference between tenure and academic homelessness.

At prestigious institutions, it can be even worse. At say The University of Louisville, if you’re a researcher with a quarter million dollar grant to study say white nose disease, you’re likely doing OK. The department is probably pretty happy with your performance, so you can throw yourself into this study without too much worry of an axe over your head. If you’re at Harvard and have this same grant, you’re likely on shaky ground. You should have more stuff on your plate and have studies planned out for the next ten years and if you don’t have time to get all the data, then you’ve got another deadline waiting around the corner. It can be tempting to make up a table or two especially if you’re ‘sure’ of the results anyway, so you can get on with the next thing or the other two projects sitting there waiting for you to finish. You may have so many that you’re hiring GRAs to do the actual work and they know that their livelihood depends upon the data just as much. How often have you had a deadline on a paper in school and ran up against it and just shoved some numbers in at the end knowing what the outcome should look like anyway? My guess is that most of us have done it at some point in our lives. Researchers aren’t saints who live in service to a higher calling. They’re just as prone to taking shortcuts as the rest of us. It’s not difficult and peers aren’t going to really check unless they come up with some outrageous result. Bottom line is that it’s actually fairly safe to say that a very large portion of research just isn’t true. It’s sad, but it’s true.

For example, the classic “Twins separated at birth IQ study” in England, appears to have been completely made up. (And IIRC was exposed by the simple question “How the heck did he find that many twins separated at birth?”) Even after it was shown to be false, it was cited, quoted and used extensively by people who hadn’t gotten the message yet.

The less provable/relevant the result, the easier to fake things. Incorrect results for the strength of structural steel will probably show up pretty quick. Preferences for sexual differences in geometric figures, for example, less so.

Fine, let’s be properly scientific then:

A vague memory of a severely dumbed down presentation of a researcher you are not naming is not a valuable contribution to fighting ignorance. There’s no accusation of pseudo-science involved in saying that the low fidelity of your presentation makes it worthless, no matter how excellent the original work might be.

Thank you for the synopsis. I had thought things like aggression or desire for social cohesion were attributed to hormones.

It works in concert and it’s reasonable to believe (though I don’t believe proven) that the hormones are what is responsible for the anatomical differences. Think of it like muscles. If an average sized guy starts taking estrogen and testosterone blockers he doesn’t suddenly become as weak as an average-sized woman. There might be some muscle loss, but he’s likely to be always stronger than a similarly sized average woman. The changes have already been made, no going back. So similarly, if a guy starts taking estrogen he doesn’t suddenly get worse at hand-eye coordination. It’s reasonable to presume that unless you have those hormones from birth, they make permanent anatomical changes to your brain.