This has literally never been true, unless you think only white Europeans define everything. See links below:
This may blow your mind, but nothing in nature is that clear-cut. Plenty of species, including humans, have genotypes that go beyond clearly-defined sexes:
Nor are there 18 million.
Gender is fakey-fake made-up bullshit! There are actually a total of 0 genders.
some people apparently don't have the guts to do the same.