While I was discussing my piece On the Character of Transgenderness with colleagues, I was induced to formulate what I think is the best argument in favor of gender essentialism, therefore providing a coherent and non-sexist basis for the concept of gender identity as understood by transgender activists and queer theory apologists.
Humanity is a gendered species and has been accumulating gendered behavior patterns for dozens of millions of years in its evolutionary species. I find it very plausible that individuals in a gendered species identify with a certain gender group in their society quite naturally. That populations would spontaneously organize themselves into two different genders is a very efficient and fool-proof way to maintain gendered behavior, and it seems quite clear to me that gendered behavior was evolutionarily advantageous for most part of our history on Earth.
If this is true, then it follows that human minds naturally categorize themselves into one gender or another, or even into a third gender if the mechanism goes haywire in some way. This implies that, even if a big chunk of gendered behavior and thought patterns, along with gender categorization of other people, may be socially constructed, there is some innate character to gender.
Still, it would be interesting if this root psychological mechanism were not inscrutable. When one asks a transgender person to explain why they feel they are, say, female, one isn’t met with a very analytical answer: I don’t know, I just feel deeply that I am female!
This unconscious and inscrutable character of gender identity is consonant with the idea that gender identity is simply innate, but it is deeply unsatisfying. To make things worse for this proposal, there is still another problem to be solved other than the inscrutable character of gender identity: why do so many cisgender people don’t experience this deep attachment to a gender? I can very comfortably picture myself into a female body and presenting myself merely as a tomboyish female human being.