Pee etiquette

It's an interesting question as to whether we just assume each other's gender identity.

I assume we do.  The same way we tend to assume each other's sexual orientation - though more and more people, if they get a whiff of someone being gay or lesbian, tend to be more careful about how they phrase certain questions.

But is it entirely proper etiquette - yet - to not assume someone's gender identity, or rather, to ask them what it is (suggesting that it wasn't clear)?

In the link above, there's a suggestion that ask someone what pronoun they prefer to be called by (e.g., him or her).  The thing is, if you ask someone who isn't transgender if they prefer to be called him or her, do you risk offending them?

Some will say that this would be akin to being offended because someone thinks you're gay - i.e., they shouldn't be offended, as it's not offensive.  But that's easier in principle than in practice.  I can imagine a woman (or a guy) being offended (or at least hurt) that I wasn't sure if she looked like a man or a woman.  And I can certainly imagine a straight guy being put off by my guessing, incorrectly, his sexual orientation, or even assuming his orientation is unclear.  Though you could certainly argue that that's his problem, not mine.

Maybe it's simply new, and it's something people need to become accustomed to.  Just as they're more accustomed now than they were before to people possibly being gay and not always being assumed straight.