On the Science of Changing Sex

Ripe Cherries…

Posted in Brain Sex, Science Criticism by Kay Brown on January 16, 2016

phrenology… or How the Science of Changing Sex is Distorted by the Transsexual Community
Funny how I have been carefully writing about the science regarding transsexuality and transgender sexuality and trying to be very careful about NOT cherry picking or distorting the evidence by either misstating or omitting key points?  Well… now I seem to have competition at The TransScience Project.  Of course, it appears that they are cherry picking or leaving out key data points.  For instance, lets examine an essay written by Sarah Lewis on “The Brain And Gender Dysphoria”:

“The first study of its kind was conducted by Zhou et al (1995). The study found sex a-typical differences in the stria terminalis of the brain stem when studying transgender subjects. A follow up study by Kruijver et al (2000) confirmed the findings and provided greater insight. The central subdivision of the bed nucleus of the stria terminalis (BSTc) is sexually dimorphic. On average, the BSTc is twice as large in men as in women and contains twice the number of somatostatin neurons. These numbers do not appear to be influenced by sexual orientation or hormone replacement therapy – and both were controlled for by Zhou and Kruijver. A paper by Chung et al (2000) studied how the volume of the BSTc varied with age in both male and female subjects. They found that the dimorphism was only prevalent in adulthood. Suggesting that the differences found by Zhou and Kruijver are not a cause of gender dysphoria but rather a result.”

Ummm… “not a cause but rather a result.”  Yes… and not quite.  No, the BSTc was influenced by exogenous hormones as a result of treating gender dyshoria, not because of gender dysphoria.  Gotta hand it to her, Lewis did a great slight of hand trick there huh?  It almost sounded like the BSTc was related to gender dysphoria… but it’s not.  Ms. Lewis failed to explain that taking hormones causes changes in the brain toward the target sex.  Not quite saying a falsehood… just letting an unwary reader be mislead.  Which is what she continues to do in the paper:

“In Luders et al. (2009), 24 trans-women who hadn’t started hormone-replacement therapy were studied via MRI. While regional grey matter concentrations were more similar to men than women, there was a significantly larger volume of grey matter in the right Putamen compared to men. As with many earlier studies, they concluded that gender dysphoria is associated with a distinct cerebral pattern.  In contrast, Savic et al (2011) did not find any sex a-typical differences in the Putaman, or other investigated areas of the brain. They did however find differences between their trans-women group and both the male and female controls.”

She didn’t mention that this research, both studies, included only non-exclusively  androphilic (i.e. primarily gynephilic) transwomen.  In fact, throughout her essay, she fails to make this distinction, which allows data that supports Blanchard’s prediction that exclusively androphilic (transkid) MTF transwomen would show shifts toward a feminized brain, but the non-exclusively androphilic would not, though they would show non-sexually dimorphic differences from both men and women, to be falsely interpreted to suggest that evidence for brain feminization in MTF transkids to apply universally.  Actually, in this case the larger volume of grey matter in the right putamen was larger than men AND women, suggestive of a non-sexually-dimorphic brain marker for autogynephilic transwomen, exactly as predicted, as explained in my essay, “And the Beat Goes On”.

Had she compared the Savic (2011) paper to the Simon (2013) paper, especially if she had quoted Simon, she might have had a far different interpretation, as I did in my earlier essay, “Shades of Grey matter”

In that paper, Simon pointed out that their study used the same methods, but found quite different results, and noted that it was because of the issue of the two types of transwomen.  Looking at only androphilic MTF transwomen, they did find that they were similar to female controls and not to male controls.  But that would not have suited Lewis to have pointed that out.  In fact, Lewis failed to note that studies which did find sexually dimorphic shifts, were conducted on exclusively androphilic transwomen,

“Two studies by Rametti et al (2011) looked at white matter differences in both trans-men and trans-women.

In their study of trans-men they found that control males have significantly higher fractional anisotropy values (FA is a measure often used in diffusion imaging where it is thought to reflect fiber density, axonal diameter, and myelination in white matter) than control females “in the medial and posterior parts of the right superior longitudinal fasciculus (SLF), the forceps minor, and the corticospinal tract”.

Compared to control females in the study, trans-men “showed higher FA values in posterior part of the right SLF, the forceps minor and corticospinal tract. Compared to control males, trans-men showed only lower FA values in the corticospinal tract.”

The study concluded that there was evidence for an inherent difference in the brain structure of trans-men.

In their study of trans-women they found that trans-women “differed from both male and female controls bilaterally in the superior longitudinal fasciculus, the right anterior cingulum, the right forceps minor, and the right corticospinal tract.” The nature of these differences suggests that some fasciculi do not complete the masculinization process in trans-women during brain development.”

However, I did point out that this only applies to exclusively androphilic transkids in my essay, “Seeing the world in grey and white”.

Lewis is not a very critical reader of the scientific literature… especially if it suits her thesis.  In fact, she accepted at face value one paper, that purported to have shown that MTF transwomen (all non-androphilic, btw) responded to human male pheromones the same as control females.  (Which is strange, because if they did respond like straight women, why aren’t they attracted to men?)  Problem?  Ummmm… nothing…. except that there’s no such thing as human pheromones!!  I pointed that out in my essay, “False (Scent) Trail”.

And speaking (er… writing) of not being critical,

“Garcia-Falgueras and Swaab (2008) investigated the hypothalamic uncinate nucleus, which is composed of two subnuclei, namely interstitial nucleus of the anterior hypothalamus (INAH) 3 and 4. They showed for the first time that INAH3 volume and number of neurons of trans-women is similar to that of control females. The study also included analysis of a single trans-man who also had a INAH3 volume and number of neurons within the male control range.”

As I pointed out in my essay, “The Incredible Shrinking Brain”, this too was easily shown to be an effect of hormone therapy, just like Swaab’s earlier report about the BSTc, in fact, these were the same subjects who had been on HRT for years, sigh…  Had she read my essay, would Lewis have included my analysis?

She concludes with one paper which suggests a difference between control men and MTF transwomen with respect to the ability to mentally rotate images.  Looking at the subject’s ages, average 37, we can see that they are likely mostly non-androphilic.  This paper looks interesting, but is this really a sexually dimorphic difference?  Or a difference in IQ?  The transwomen were about IQ 107-109 and the control men, who performed better, were about IQ 123 (a significant difference at one standard deviation).  Me?  I’m going with IQ.

This isn’t the only example of cherry picking I’ve commented upon, as I wrote in an earlier essay, “Gender Allusions”.

So, we see that when looking at the scientific evidence and how it is presented, by and within, the transcommunity clearly wants to believe, and leave others with the impression, that it supports the notion that all transwomen have feminized brains and that there is only one kind of transwomen.  Sadly for them, neither is true.

Further Reading:

Essays on Brain Sex

Cherry Picking at Scientific American {Author uses only papers w/ exclusively androphilic subjects.}

 

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