Neuro-biology of trans-sexuality : Prof. Robert Sapolsky

The autopsy studies were done by Dick Swaab, and repeated, here's one of his articles from 2008 (I'm sure you can find the rest on your own):

Garcia-Falgueras A, Swaab DF. A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity. Brain. 2008 Dec;131(Pt 12):3132-46. doi: 10.1093/brain/awn276. Epub 2008 Nov 2. PMID: 18980961.

for a video overview on the science I recommend this overview by Julia Serano: https://www.youtube.com/watch?v=ZymYiwoRoC0

This video overview on the variability of sex is also highly recommended: https://www.youtube.com/watch?v=nVQplt7Chos

there were some MRI studies by Joel et al. that disrupted the overly simple findings of the autopsy studies:

Joel D, Berman Z, Tavor I, Wexler N, Gaber O, Stein Y, Shefi N, Pool J, Urchs S, Margulies DS, Liem F, Hänggi J, Jäncke L, Assaf Y. Sex beyond the genitalia: The human brain mosaic. Proc Natl Acad Sci U S A. 2015 Dec 15;112(50):15468-73. doi: 10.1073/pnas.1509654112. Epub 2015 Nov 30. PMID: 26621705; PMCID: PMC4687544.

and for a more up to date article with a collab between Joel & Swaab, I would check-out:

Joel D, Garcia-Falgueras A, Swaab D. The Complex Relationships between Sex and the Brain. Neuroscientist. 2020 Apr;26(2):156-169. doi: 10.1177/1073858419867298. Epub 2019 Sep 11. PMID: 31509086.

also worth reading:

Saraswat A, Weinand JD, Safer JD. Evidence supporting the biologic nature of gender identity. Endocr Pract. 2015 Feb;21(2):199-204. doi: 10.4158/EP14351.RA. PMID: 25667367.

Korpaisarn S, Safer JD. Etiology of Gender Identity. Endocrinol Metab Clin North Am. 2019 Jun;48(2):323-329. doi: 10.1016/j.ecl.2019.01.002. Epub 2019 Mar 18. PMID: 31027542.

Ainsworth, C. Sex redefined. Nature 518, 288–291 (2015). https://doi.org/10.1038/518288a

and finally this systematic literature review on the clinical outcomes of trans gender-affirming healthcare:

https://whatweknow.inequality.cornell.edu/topics/lgbt-equality/what-does-the-scholarly-research-say-about-the-well-being-of-transgender-people/