@KonradRudolph I think they used male and female as nouns (as I often do) because the thing that matters the most at the moment about them is their gender. You could replace it with "a male|female specimen of Homo Sapiens species", but since the only relevant part of all of that is that they are of said gender you just use "a male|female" omitting the rest. Moreover Homo Sapiens is an animal as well, so why would it be wrong to call ourselves accordingly?

@FabioR. But for humans there are more specific terms: “man” and “women”. Purposefully avoiding them is what’s weird.

As a biologist I’ve obviously no issue with treating humans as part of the animal kingdom. I do have a problem with intentional de-humanising language in a non-biological context.

@FabioR. Interestingly, I would normally use man and woman to specify gender and male and female to specify sex.