There's quite a bit of talk about gender identity. For the sake of semantics :
Sex vs gender
Sex is a wholy biologically determined characteristic. It is mostly binary but not purely binary, and this is nothing new to the medical world. Sex is an immutable characteristic. Primary determinants are genetic. Secondary determinants being Environmental meaning of hormonal/chemical/nutrition.
Gender is often confused with sex.
Gender is traditionally binary, men and women, almost exclusively determined by sex (male female). However gender determinants are biological, developmental/environmental, and cultural. This means that new cultural understandings are creating space for additional gender identities and the gender is not treated as a determinatistic characteristic, or even an immutable characteristic. Sadly I think our society has become stuck on the term identity with gender when it may be better to use a word that has a meaning closer to personality, and individuals in a culture confused about their identity hyper focus on the traditional sexual determinants set as something that must be changed to match personality. How many genders are there, is it on a Spectrum, if it's a spectrum then how many axes are there on the Spectrum... these are difficult questions because the answers are found at the collision point between science, culture/tradition, opinion/emotion.
I think it's a topic worthy of its own thread and shouldn't distract from this thread.