https://www.tandfonline.com/doi/full/10.1080/00332925.2017.1350804I find this article interesting.
''Gender is between the ears, not the legs, we are told.
Transgender author and activist Serano (2007) tells us that we all have a subconscious sex—a deeply innate sense of gender. It is this subconscious sex, rather than our physical sex, that determines who we really are. Therefore, “feeling like a woman” or “identifying as a woman” is to be a woman.
However, to date, the notion of an innate gender identity is not supported by science. Although there is some evidence of a biological basis for the development of gender dysphoria (Heylens et al., 2012), we are far from being able to claim that there is an empirical basis for believing that one is “trapped in the wrong body,” has a “female” or “male” brain, or even a “gender identity” that doesn't match one's body. Though the concept of gender identity is currently being enshrined into law, the truth is that we have no meaningful definition of the term.""