Around 0.3% of the population in the US can be identified as transgender, so that knocks it down to 99.7%. Then there's other factors, where people don't adhere to any particular binary gender at all, which erodes that even further.

When you include the full spectrum of LGBTQI you probably have to cut that down to no more than 95%, possibly less.

When you say "for the vast majority" you presume they operate in isolation, but they don't. Most people will end up knowing at least one person that doesn't conform to the traditional gender patterns, which means it's a problem everyone faces.

I was talking about the T (since the question was how come someone doesn't get that sex != gender). The LGB part is a lot more, some estimates are even around 10%. The "gender issue" is almost 2 orders of magnitude smaller than the sexual orientation issue.

So that's the explanation why most people don't "get" or even think about the distinction, but they know about gays and lesbians.

I've known three, and I don't have an awful lot of friends and acquaintances. I also don't go out of my way to only talk to LGBTQI folks. (I do, however, go out of my way to talk to people interested in technology and especially computer security.)

If you pool the various genetic causes of intersex conditions (neither unambiguously male nor unambiguously female) it's about the same percent of the population as natural red hair. Should we ignore people with red hair?

I'm not saying we should ignore them. Just that for most people the two concepts "sex" and "gender" aren't separate, and trans people are simply regarded as quirky. For example there are people born with 6 functional fingers per hand but we still say that humans have 5 fingers per hand and don't say that humans have anywhere between 0 and 8 fingers per hand.

Treating sex and gender separately makes it seem like they just accidentally coincide in case of 99.x% of the people.

> It's a niche thing.

One needs a very special kind of schooling and/or social circle to even imagine there's a difference. It seems to be very limited to (some) Americans.

Some people suffer from phantom limb syndrome. The pain is real, but the limb is not. We've not yet reached a point where the politically correct thing to do is to pretend otherwise.

Everyone understands that in the vast majority of times we use man/woman, he/she, or him/her, the intention is not to specifically draw attention to a person's reproductive organs. It doesn't take special schooling to detect this distinction, though it does require some thought to figure out what to make of it.

There would only be PC pressure to pretend a trans man has a penis if "having a penis" were a vital component of being a man, which it is not. In any case, the circumstances under which one finds themselves having to confirm the presence/character of another persons genitals usually either fall outside of or supersede the jurisdiction of "political correctness".