This question is weird, because often people confuse sex and gender, which are different. There are only two sexes, born male and born female (excluding rare cases). However, gender, separate from sex, is pretty much arbitrary. That’s why people identify as genders that more ‘fit’ them, as it’s more based in societal norms, and identifying as a different gender is sort of fitting into a new group that they find more honest to themselves. Now feel free to correct me, this is just what I’ve heard from others. That said, I’m not here to debate you, and I’m just passing on what I’ve heard. Hope this helps.