I hate to break it to you but there have always been more than 2...

I hate to break it to you but there have always been more than 2 genders, or rather people that fitted into neither / both.
Nothing to do with 'identifying as' or any such thing but pure biology.

People who are intersex have genitals, chromosomes or reproductive organs that don’t fit into a male/female sex binary. Their genitals might not match their reproductive organs, or they may have traits of both. Being intersex may be evident at birth, childhood, later in adulthood or never. Being intersex isn’t a disorder, disease or condition.