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RE: brain structural differences in FtMs and MtFs.
many of you have seen the argument that transwomen have female brains and that transmen have male brains. however, the studies referenced usually specify a difference between nonhomosexual and homosexual trans brain differences
many of you have seen the argument that transwomen have female brains and that transmen have male brains. however, the studies referenced usually specify a difference between nonhomosexual and homosexual trans brain differences
which is often conveniently ignored. for example, simon et al (2013) found that homosexual MtFs and female controls had less gray matter volume in some areas than male controls and FtMs https://pubmed.ncbi.nlm.nih.gov/24391851/
in another example, zubiarre-elorza et al (2013) compared homosexual MtFs with female and male controls to study cortical thickness (CTh). MtFs did not differ in CTh from female controls but their CTh was greater than that of control males in some areas https://pubmed.ncbi.nlm.nih.gov/22941717/
differences in white matter are more complex, according to rametti et al (2016). homosexual MtFs differed from both male and female controls bilaterally in superior longitudinal fasciculus and some areas of the right hemisphere https://pubmed.ncbi.nlm.nih.gov/21195418/
now letâs looks at how studies diverge when nonhomosexual MtFs are included in samples. according to savic & arver (2011) nonhomosexual MtFs have the same intracranial volume as males, and show a larger gray matter volume than both male and female controls https://pubmed.ncbi.nlm.nih.gov/21467211/
more from savic & arver, emphasis mine: their data did not support the notion that the nonhomosexual MtF brain was feminized.
luders et al. (2009) included more nonhomosexual FtMs than homosexual FtMs in the sample and has similar findings. they found the pattern of grey matter variation in MtFs was more similar to the pattern found in men than in women https://pubmed.ncbi.nlm.nih.gov/19341803/
so why does it matter if a study includes homosexual or nonhomosexual MtFs, you may ask. well, because many studies have concluded that homosexual men in general have similarities in brain structure to the typical female brain.
for example, manzouri & savic (2018) found homosexual males displayed âfemaleâ characteristics, with a similar Cth in the left superior parietal and cuneus cortices as heterosexual females, but different from heterosexual males https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0203189
similarly, savic and lindström (2008) found the brains of heterosexual men and homosexual women are slightly asymmetric, while the brains of gay men and straight women are not. also, lesbians resemble straight men & gay men resemble straight women in connectivity of the amygdala
ref for previous tweet https://www.pnas.org/content/105/27/9403
in conclusion, it could be argued that differences in brain structures between MtF transgender people and male people, as well as differences between FtM transgender people and female people, could be due to homosexuality and not gender dysphoria
if you hung around this long, thank you! this is my first thread so please feel free to share your thoughts. i am eager to improve for the future.
