Originally a comment by Sastra on Well ask yourself.

So gender identity would be to identify with the norms, values, expectations, practices, and beliefs a society has placed on the sexes.

Here’s the problem, though: the common claim made by people who insist that Gender Identity is more significant than sex is that GI has no direct relation to the norms, values, expectations, practices, and beliefs a society has placed on the sexes. It’s pure. Its existence is not influenced by culture, but culture will influence a trans girl to behave in a feminine manner in the same way a cis girl is influenced by her environment. Trans people are no longer said to identify with or as a gender, but to be that gender. And by “gender” they mean “sex, but without all that stuff specific to reproduction.” Or it could be something else by now.

It’s hard to pin down the meaning of “identity” in a system which keeps creeping into what it’s being contrasted with. They used to allow “male” and “female” to be sex words. Now a transwoman is female, who doesn’t identify as female, but is as a matter of fact. It says so on the official certificate.

The meaning of “gender identity” I find the least problematic is the one which has been used for decades in the study of early childhood development. How does an infant boy gradually come to recognize that he’s a boy and figure out what that means? When does a young girl understand the distinction between following the shifting rules about being feminine and the implacable truths about being female?

If we start from scratch, at some point there’s a series of moments where our growing understanding of self jostles around our sex. Babies start out needing to learn the distinction between self and other. I’m okay calling that “identity formation” partly because I can’t think of what else to call it.