[faeriechangling]

That certainly plays into the unpopularity of the concept, but even independent of that, this doesn't address the central criticism that autistics seem to be more likely to be MtF transgender.

We know that MtF transgender people that the brains of transgender women resemble the brains of cisgender women, than the rains of cisgender men resemble the brains of cisgender men.[1] Transgender women have extremely androgynous brains, not extreme male brains.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8955456/

Generally, if you rephrase the concept as the "Emphasising-Systemising theory of autism" it becomes a lot less implausible. "Extreme maleness" implies being more male across the board to an extreme, and that does not appear to be the case with autistics, they might have a few male-coded traits but they're not extremely male.

[neurowned]

> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8955456/

That study, and others with similar results, do not control for sexual orientation - even though it's already well established that homosexuality correlates with some brain structures being atypical for one's sex.

In the studies that do control for sexual orientation, no such shift towards the opposite sex is found to correlate with gender dysphoria.

Instead, what has been shown are differences in structural and functional connectivity within the default mode network of the brain, which is essential for body perception and self-referential processing. See for example https://www.nature.com/articles/s41598-017-17352-8.