I think you are mistaken gender for sexuality, sexuality (the ability to reproduce) in humans it's still only male or female (while fungi actually reproduce though different forms, that differ massively).
But there there are also those who are not specifically male or female, thus intersexual (derived from intermediate sexuality).
But gender is more about an expression of how you "feel", that's why it's transgender because an actually transition to another sex completely, is not possible yet.
And gender is actually more complex than most people know or can image.
https://www.itspronouncedmetrosexual.com/articles/of-course-biological-sex-is-real/
https://www.itspronouncedmetrosexual.com/2018/10/the-genderbread-person-v4/