Saturday, 14 January 2017

Brain differences in transsexuals

Heya again,

two posts in a row (to make up for the long hiatus?) 😏

This study is perfect to complement my last post, which was also about brain differences in transsexuals.

A new study by Guillamon, Junque and Gómez-Gil is called A Review of the Status of Brain Structure Research in Transsexualism (Archives of sexual behavior, 2016). They find:

Cortical thickness and diffusion tensor imaging studies suggest that the brain of MtFs presents complex mixtures of masculine, feminine, and demasculinized regions, while FtMs show feminine, masculine, and defeminized regions. Consequently, the specific brain phenotypes proposed for MtFs and FtMs differ from those of both heterosexual males and females.

Reviewed were studies about the brain structure of male-to-female (MtF) and female-to-male (FtM) homosexual transsexuals before and after cross-sex hormone treatment.

I’d say that’s another study providing evidence for the view that brain structures of transsexuals differ from those of cisgender people.

Peace and Light ✨

A YouTube video claims there is no evidence of a biological basis for transgenderism

Heya everybody,

happy new year, health and happiness to everybody ✨

Reader Alice, a young transgirl, was so kind to send me a link to a YouTube video by someone named Nicolas Kilsdon-Gervais, who claims to have extraordinary knowledge of what he’s talking about.

His point is that there is no biological evidence for transgenderism (as the headline says, sorry for the repetition). He starts by citing a number of studies about brain differences between cisgender and transsexual brains. All the relevant studies he cites, except for one, have been included on my website some time ago (phew - I did a decent job then 😏).

The studies he starts with are: Hoekzema, Schagen, et al. (Psychoneuroendocrinology, 2015) and Savic and Arver (Cerebral cortex, 2011).

These two studies are included in the references section 1.c: brains of transsexuals differ from their birth gender of my website. Both studies do find differences between transssexual brains and brains of a cisgender control group of the respective natal gender. Here are Hoekzema and Schagen:

However, region of interest analyses indicated less GM [gray matter] volume in the right cerebellum and more volume in the medial frontal cortex in female-to-males in comparison to girls without GD [gender dysphoria], while male-to-females had less volume in the bilateral cerebellum and hypothalamus than natal boys. Deviations from the natal sex within sexually dimorphic structures were also observed in the untreated subsamples. […] However, there are subtle deviations from the natal sex in sexually dimorphic structures, which can represent signs of a partial sex-atypical differentiation of the brain.

Savic and Arver state:

MtF-TR displayed also singular features and differed from both control groups by having reduced thalamus and putamen volumes and elevated GM [gray matter] volumes in the right insular and inferior frontal cortex and an area covering the right angular gyrus.

Nicolas Kilsdon-Gervais is correct when he states that neither study finds that transsexual brains are similar or identical to cisgender brains of their target gender. Both studies explicitly say so. But what Nicolas Kilsdon-Gervais doesn’t consider properly is that some differences between transsexual brains and cisgender brains of their natal gender have been found.

This is what to to expect if the theory of an innate biological gender identity is true: Imagine, for example, a female brain put in a male body. The male body does flood the brain with male sex hormones. The result will be brain structures that are different to both male and female cisgender brains.

The next study he’s citing is Kreukels and Guillamon (International review of psychiatry, 2016) (that’s the study I have to yet include on my website). What do they say?

Findings from neuroimaging studies focusing on brain structure suggest that the brain phenotypes of trans women (MtF) and trans men (FtM) differ in various ways from control men and women with feminine, masculine, demasculinized and defeminized features.

So, it’s the same things again – the authors see differences between transsexual brains and brains of cisgender people. I think this contradicts the point Kilsdon-Gervais is trying to make.

I can’t analyse the full video at this time, but I think this sums up the part about brain differences. My conclusion is that Kilsdon-Gervais is wrong, and probably quite biased against transpeople.

Peace and Light ✨