The Brains of Men and Women Aren't Really That Different, Study Finds (sciencemag.org)

sciencehabit writes: In the mid-19th century, researchers claimed they could tell the sex of an individual just by looking at their disembodied brain. But a new study (abstract) finds that human brains do not fit neatly into "male" and "female" categories. Indeed, all of our brains seem to share a patchwork of forms; some that are more common in males, others that are more common in females, and some that are common to both. The findings could change how scientists study the brain and even how society defines gender.

Comments

Re:This is not in the least surprising

[tlhIngan]

There've been lots of studies finding "psychological differences between the sexes". But when you look into them the statistical correlations are usually terribly weak, barely above statistical significance. And you have to question how much you can trust them anyway. Remember that metastudy that showed that half of all psychological studies can't be reproduced? I downloaded their study data. Every topic related to gender differences was in the "couldn't be reproduced" category. Now, of course that's a tiny fraction of all research that they attempted to reproduce. There surely are psychological differences, even ones that aren't pure upbringing/society related. But its important not to overplay the amount or degree of them.

I'm not surprised, really.

Everyone basically starts out a female from conception - the X chromosome asserts itself during the first 5-6 weeks before the Y chromosome (only in males) starts to activate, at which point the SRY gene activates that inhibits certain genes in the X chromosome and to start turning you male. The developing ovaries descend and become the testes, the clitoris transforms into the penis.

And with that in mind, it should be obvious why there are trans-gendered or bisexual people as well - a fallout of the natural process of gestation and sometimes, things don't always go completely as planned.

Life is complicated. And differences really are fairly minor.

Re:Definitions

[BarbaraHudson]

Want to try again? Here, please educate yourself

In the 1990s, scientists began to compare these sexually dimorphic regions in the brains of transsexuals and the rest of humanity. Early work in this area required the examination of brains postmortem; recent studies use images of the living brain.

The results show that when individuals of Sex A—despite having the chromosomes, gonads and sex hormones of that sex—insist that they're really Sex B, the gender-affected parts of the brain typically more closely resemble what's usually seen with Sex B.

Consider an obscure brain region called the forceps minor (part of the corpus callosum, a mass of fibers that connect the brain's two hemispheres). On average, among nontranssexuals, the forceps minor of males contains parallel nerve fibers of higher density than in females. But the density in female-to-male transsexuals is equivalent to that in typical males.

As another example, the hypothalamus, a hormone-producing part of the brain, is activated in nontranssexual men by the scent of estrogen, but in women—and male-to-female transsexuals—by the scent of androgens, male-associated hormones.