there is no numerical value that can encapsulate the endlessness of "possible different gender identities"
gender is part of the complexity of the human personality and it is natural, not man-made
it's too obscure and too fluid for it to be associated with some sort of system of probable outcomes
and, furthermore, it is important to remember that, when we talk about gender, we are using words to describe a concept
words are and always will be flawed because they are a tool created by humans and humans are limited beings
there is no "amount" of genders
gender simply is
don't get so caught up in trying to categorize things that you lose the understanding of what they actually are