Any scientific studies proving the physical origins of gender dysphonia?

Factual Questions
1

A common claim about gender dysphonia (aka transgender/transsexual) is that affected individuals have a brain of one gender and the physical characteristics of another.

Are there any studies validating (or disproving) this claim for a probable majority of affected people? I know it’s not feasible to test everybody (even of such a relatively small population), but most proper studies can be extrapolated to the entire population with a known degree of reliability.

Please, no anecdotes or “you’re a hater”-type comments. The first isn’t statistically significant, and the second is irrelevant (even if it were true).

2

Dysphoria. That means feeling really bad.
Dyphonia means talking like Diane Rehm.

3

That should be: Dysphonia means talking like Diane Rehm. Caught the typo too late for edit.

4

First of all, we would have to have a good understanding of the differences (if any) between the brains of regular men and women. I do not think we have that.

That is not to say that there are not any differences or that we have no idea at all what differences there might be, but evidence for systematic, sex-related differences is weak, and what differences there are are probably not going to be obvious just by looking at a brain’s gross anatomy, and may well generally fall well within the range of normal variation within each sex. (There is actually quite a lot of variation in individual brain anatomy, most of which has nothing to do with sex, and much of which, so far as we know, is not reflected at all, at least in any very obvious ways, in mental traits or abilities. Any sex-related differences that may exist are likely to be hard to see amongst all this “noise”.)

When it is claimed that people with gender dysphoria have a brain that is the opposite sex to that of the rest of their body, I think this is just a way of making the claim that they have a mind that is the opposite sex to that of their body sound more sciencey and objective than it really is. It is one of the many forms of neurobollocks that currently infest pop-science discourse. In fact, science can do a much better (though still far from perfectly reliable) job of distinguishing masculine from feminine minds (through things like psychological tests - or even just asking people questions about how they feel about their sexuality) than it can of distinguishing masculine from feminine brains (via MRI scans, or whatever).

5

http://www.gires.org.uk/Text_Assets/maletofemale.pdf warning PDF

6

Yeah, like you can find a Bible verse to support anything you want, these days you can find a neuroscience article somewhere or other to support anything you want (and probably its opposite). I stand by my previous post. It’s neurobollocks.

7

What exactly is wrong with the study? Why precisely is it “neurobollocks”?

8

What is the basis for your opinion? Are you a neuro-scientist that is current on research in this area?

Based on googling and reading studies, there appear to be a substantial number of researchers that disagree that the evidence for some structural differences is weak.

9

That neuro paper doesn’t really seem all that decisive. Check out these findings (bolding mine):

See that last P value? That means that even if there were in reality no differences between the numbers of SOM neurons in a natal man’s brain and a trans-woman’s brain, we would expect to, purely by chance, measure different numbers in those brains that we happen to have on hand fully 83% of the time that we perform an experiment using that sample size (that is, looking at the same number of brains that they looked at in the study).

The reason that number is so high is because like many biological parameters, SOM numbers exhibit a high person-to-person variability, and since the size of their sample is so small (they only had 3 MtF brains to study!), it is unfortunately difficult to be sure that the numbers you measured in those brains accurately represent the true average values that you’d get if you were able to measure the SOM numbers in everyone’s brain, ever.

So if this paper is the only thing backing up the assertion that trans-folks’ brains are more similar to the brains of their goal sex than they are to those of their natal sex, then I’d say that no, it’s not a justifiable assertion. We’d need to study way more brains than they did in this paper to come to a solid conclusion on that.

10

Reading the technical paper, rather than an abstract, reveals more information which is interesting, however.

From the original paper:

I have a paper reviewing the physical evidence of transsexuality in review stage now and don’t want to quote from it too extensively. When it’s done, I can maybe provide a link to my trans website.

11

I’m reluctant to get into this subject because it typically draws trolls and haters who know just enough science to sound impressive without actually saying anything one way or another. I’ve spent just over a hundred hours working on reviewing this subject, and here are some references to consider. Of the ones listed, Emory, Haraldsen, Ludens, Hengstschläger, and Savic probably contain the most anti-physical or anti-genetic evidence. The rest contain pro-physical or pro-genetic evidence.

Balen, Adam H., et al. “Polycystic ovaries are a common finding in untreated female to male transsexuals.” Clinical Endocrinology 38.3 (1993): 325-329.

Bao, Ai-Min and Swaab, Dick F. “Sexual differentiation of the human brain: Relation to gender identity, sexual orientation and neuropsychiatric disorders” Frontiers in Neuroendocrinology 32 (2011): 214–226.

Berglund, H. et al. “Male-to-Female Transsexuals Show Sex-Atypical Hypothalamus Activation When Smelling Odorous Steroids” Cerebral Cortex 18 (August, 2008): 1900—1908.

Cantor, James M. “New MRI Studies Support the Blanchard Typology of Male-to-Female Transsexualism” Arch Sex Behav 40 (2011): 863–864.

Coolidge, Frederick L., Linda L. Thede, and Susan E. Young. “The heritability of gender identity disorder in a child and adolescent twin sample.” Behavior Genetics 32.4 (2002): 251-257.

Dessens, Arianne B., et al. “Prenatal exposure to anticonvulsants and psychosexual development.” Archives of Sexual Behavior 28.1 (1999): 31-44.

Dorner, Gunter, et al. “Genetic and Epigenetic Effects on Sexual Brain Organization Mediated by Sex Hormones.” Neuroendocrinology Letters 22.6 (2001): 403-409.

Emory, Lee E., et al. “Anatomic variation of the corpus callosum in persons with gender dysphoria.” Archives of Sexual Behavior 20.4 (1991): 409-417.

Fontanari, Anna-Martha V. et al. “Serum concentrations of brain-derived neurotrophic factor in patients with gender identity disorder” Journal of Psychiatric Research (2013): 1-3 (advance copy).

Futterweit, Walter, Richard A. Weiss, and Richard M. Fagerstrom. “Endocrine evaluation of forty female-to-male transsexuals: Increased frequency of polycystic ovarian disease in female transsexualism.” Archives of Sexual Behavior 15.1 (1986): 69-78.

Gooren, Louis “The biology of human psychosexual differentiation” Hormones and Behavior 50 (2006): 589–601.

Green, Richard, and Eric B. Keverne. “The disparate maternal aunt–uncle ratio in male transsexuals: an explanation invoking genomic imprinting.” Journal of Theoretical Biology 202.1 (2000): 55-63.

Green, Richard. “Family cooccurrence of “gender dysphoria”: Ten sibling or parent–child pairs.” Archives of Sexual Behavior 29.5 (2000): 499-507.

Haraldsen, I. R. et al. “Sex-sensitive cognitive performance in untreated patients with early onset gender identity disorder” Psychoneuroendocrinology 28 (2003): 906–915.

Hare, Lauren et al. “Androgen Receptor Repeat Length Polymorphism Associated with Male-to-Female Transsexualism” Biol Psychiatry 65.1 (January 1, 2009): 93–96.

Hengstschläger, Markus, et al. “Sex chromosome aberrations and transsexualism.” Fertility and sterility 79.3 (2003): 639-640.

Hines, Melissa, Charles Brook, and Gerard S. Conway. “Androgen and psychosexual development: Core gender identity, sexual orientation, and recalled childhood gender role behavior in women and men with congenital adrenal hyperplasia (CAH).” Journal of Sex Research 41.1 (2004): 75-81.

Italiano, M. “Comment on Cantor” Arch Sex Behav 41 (2012):1079.

Khandelwal, Ashish et al. “A 47,XXY Female with Gender Identity Disorder” Arch Sex Behav 39 (2010):1021–1023.

Kruijver, Frank P. M. et al. “Male-to-Female Transsexuals Have Female Neuron Numbers in a Limbic Nucleus” The Journal of Clinical Endocrinology & Metabolism 85.5 (2000): 2034-2041.

Luders, Eileen et al. “Regional gray matter variation in male-to-female transsexualism” Neuroimage 46.4 (July 15, 2009): 904–907.

Meyer-Bahlburg, Heino FL. “Transsexualism (“Gender Identity Disorder”)–A CNS-Limited Form of Intersexuality?.” Hormonal and Genetic Basis of Sexual Differentiation Disorders and Hot Topics in Endocrinology: Proceedings of the 2nd World Conference. Springer New York, 2011.

Oh, Seok-Kyun et al. “Brain Activation in Response to Visually Evoked Sexual Arousal in Male-to-Female Transsexuals: 3.0 Tesla Functional Magnetic Resonance Imaging” Korean J Radiol 2012;13(3):257-264

Rametti, Giuseppina et al. “White matter microstructure in female to male transsexuals before cross-sex hormonal treatment. A diffusion tensor imaging study” Journal of Psychiatric Research 45 (2011): 199-204.

Rametti, Giuseppina et al. “Effects of androgenization on the white matter microstructure of female-to-male transsexuals. A diffusion tensor imaging study” Psychoneuroendocrinology 37 (2012): 1261—1269.

Sabalis, Robert F. et al. “The Three Sisters: Transsexual Male Siblings” Am J Psychiatry 131 (August 8, 1974): 907-909.

Sadeghi, Majid, and Ali Fakhrai. “Transsexualism in female monozygotic twins: A case report.” Australasian Psychiatry 34.5 (2000): 862-864.

Savic, Ivanka and Arver, Stefan. “Sex Dimorphism of the Brain in Male-to-Female Transsexuals” Cerebral Cortex 21 (November, 2011): 2525—2533.

Swaab, D.F. “Sexual differentiation of the human brain: relevance for gender identity, transsexualism and sexual orientation” Gynecol Endocrinol 19 (2004): 301–312.

Yokota, Y. et al. “Callosal Shapes at the Midsagittal Plane: MRI Differences of Normal Males, Normal Females, and GID” Proceedings of the 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference Shanghai, China, September 1-4, 2005.

Zhou, Jiang-Ning, et al. “A Sex Difference in the Human Brain and its Relation to Transsexuality.” Nature 378.6552 (1995): 68-70.

Zubiaurre-Elorza, Leire et al. “Cortical Thickness in Untreated Transsexuals” Cerebral Cortex Advance Access, published August 31, 2012.

Zucker, Kenneth J., et al. “Psychosexual development of women with congenital adrenal hyperplasia.” Hormones and Behavior 30.4 (1996): 300-318.

12

First, as I recall some of the differences between male and female brains - and between the brains of transgender people and non-transgender people, are visible to the naked eye. And in fact, only to the eye in at least one case, a speckling on part of the brain; brain scans can’t pick it up yet, it can only be seen by opening up the brain and looking.

And the difference in male and female brain structure is large, not subtle. The idea that men and women are alike on the inside is one driven by politics, not science. We are more different than we appear, not less.

Personally I find it interesting that we are so different on the “hardware” level but appear to be so similar on the conscious level. I mean, I’ve read stories and personal accounts written from a female viewpoint written by women (the closest I can get to getting inside the mind of a woman, naturally), and they don’t come across as the aliens that I’d expect just from looking at the differences in anatomy.

13

There do seem to be trans people who are fixtated on very strict interpretations of gender roles. Maybe if we got RID of gender roles, there wouldn’t be trans people…

14

No, because we still want our bodies to be as close as possible to what they should be (meaning, to match our mental gender). As far as getting rid of gender roles so entirely that the only difference between men and women is that women can bear children…not going to happen in the next thousand years, and I’m not certain it’s all that good of a thing either.

I will confess, however, once I came out 100% and was accepted with opened arms at work, socially, family, etc., it relieved about 75% of all my gender dysphoria. Hormones relieved about 20%, and the remaining dysphoria is easily manageable. It’s an irritation, like an allergy, rather than a life-threatening illness.

Other girls, some of them my good friends, are out socially like me, but still are probably 50% or more dysphoric, obsessing over SRS and other surgeries. They’re neither right nor wrong, just different from me.

15

The alliance between the MRA-style “women are an alien species” folks and the super progressive trans activists on the issue of gender being absolutely and totally biological is uh, interesting to say the least.