There are multiple genders. There always have been. Nobody ever manages to actually refute this, and people who try generally end up resorting to insults.
Fairly sure if you were to ask my relatives who were alive in 1920, they wouldn't come up with 'multiple genders' as a concept. Male and Female sexes, yes. But beyond that, nope.
There haven't always been multiple genders.
I think this can be fairly easily refuted by looking at historical documents. It is not a concept that has existed in this country or culture.
Identities may differ culturally around the world, but not universally and not in the way gender exists now. They were previously more social statuses and personalities. And were not open to all classes in society.