[p2detar]

Well, my point was not about accepting or not accepting it. I have no issue with that.

My issues is that it would be hard for me personally to write an Email to several different people with different gender pronouns. I was asking if there are alternatives or maybe even similar situations in other cultures/languages that might hint to a more general solution.

It seems I was not clear enough, hence the downvotes above.

[pseudalopex]

The general solution in most if not all cultures is not allowing what you're worried about. Some languages don't have pronouns. Some just have gender neutral pronouns. Some have gendered and neutral pronouns.

Some cultures have 4 or 5 genders. But their systems wouldn't work in English speaking cultures where trans men and women identify as just men and women.