> Let's be honest here, "non-binary genders" is a weird concept to begin with. It's alien and doesn't apply to humans.
It's actually a lot more prevalent in the population than some people realise. It's not something that was made up. For example, odds are, you almost certainly know a few people who are intersex one way or another, but they might not share this information freely with you.
Simply not having XX nor XY chromosomes happens about in one in every 1666 people. Surely you have met at least two thousand people in your life.