Gender doesn't equal sex, though. My non binary friends are very much equipped with penises or vaginas.
There's a wide variety of genders in the rest of the world as well. While this is a newer concept in American and Western cultures, there are non male, non female genders dating back to mesopotamia.
My point is just that more specific terminology should be used. Your friends have nonbinary gender presentation, but that doesn't make their gender something other than male or female.
And sure, there's historically been a wide range of gender roles, norms, and expectations, but there's only ever been two genders.
There's a wide variety of genders in the rest of the world as well. While this is a newer concept in American and Western cultures, there are non male, non female genders dating back to mesopotamia.