Sex is a biological trait, gender is a psychological one, it’s behavioral patterns, nothing else. So whereas there are only 2 sexes (barring birth defects which do happen), there can be a miltitude of gender identities as a reflection of how one views oneself when it comes to the matters of sexuality.

The truth is, there are no genders whatsoever. Zero. All gender identities are socially constructed or self-constructed, we assume them unconsciously because we don’t know any better. Both women and men suffer from their gender identity, and all queer people suffer even more, because it’s less socially acceptable. To consciously create and prop up a gender identity is a sign of insanity. This rarely happens, however, as gay people will tell you that there was never a conscious moment when they “decided” to be gay, at most they just realized it. Gender identities are almost entirely unconscious.