Western cultures in the past couple decades have started acknowledging this, but the concept is not foreign to all countries.

And the changes proposed are to include as many people as possible. You might say, people are typically born with two arms, sometimes fewer. It doesn't remove the fact that most people express as 2 armed, while including the people who don't.

I believe that we can be inclusive of those exceptions and treat them as unique things that are within the definition, rather than placing them outside the definition. I would rather spend the energy to evolve definitions to include people rather than tell people they are marginalia.

It sounds like you disagree.

It is not inclusive to call a woman a “birthing person” it’s actually excluding the women who can’t give birth. Are women who can’t become pregnant men? Of course not.

We have let politeness run away with us. It’s time to kindly, but firmly tell people there are two genders. It’s not a kindness to lie to a person, even if they ask for the lie.

Not out of the group of "women", so "Are women who can’t become pregnant men?" doesn't make sense.

Woman who can't give birth are still women. Women who cannot menstruate are still women. We are not removing anyone from the set of women.

What we are saying is that, in addition to women there are also people who do not recognize themselves as women, but who can give birth or menstruate.

So, we could say "women, men, and other gendered people who give birth..." or "birthing women, men, and other gendered people".

But that's a mouthful. All genders are people, so we choose "people who give birth" since it includes women AND people who are not women.

So yes, it's inclusive because it's including women and not women, rather than only women.

People 'typically' have two arms?

Well they 'typically' also have two legs, a sense of smell, sight, hearing, a heart, two lungs, the ability to speak.

What exactly can we expect all 'humans' to have? And how can we refer to them without making any assumptions whatsoever about their state of being so as to be 'inclusive' as you say?

It's a Monty Python sketch of absurdity and will end up with people slapping others in the face with fish.

Aside from probably using 'they' or 'them' in some cases in which we didn't tend to before, language as we use it is perfectly fine in almost all cases. It never will perfectly encompass everyone and that's fine, it doesn't have to.

This question answers itself, no? You can refer to them as 'humans'.

I'm happy to use he, she or they, because it's reasonable and rational but beyond that it's all shenanigans, I have no time for it.

What's it called? What's an example of a person of that gender?

What gametes do they have? What chromosomes?

In mesopotamia, mesoamerica, and the Indus valley there were people of unclear sex who fulfilled genders beyond men and women.

A neologism from pan indigenous culture is Two Spirit.

These concepts have existed for a loooong time, however they were quite rare in western countries. As westerners, we're being exposed to them now, but they are hardly novel on the world stage.

Fact remains, there is no third sex. Intersex is not a third sex and sexual anomalies also do not introduce a third sex.

Gender isn't sex.