If or better yet when, you meet a trans person, regardless of how you personally feel about them, at least show them the same respect you would show for anyone else. That means addressing them by their preferred pro-nouns (he, she, they, them, it) and name (self-explanatory).
It's easy, and it'll make you look like a much better person.
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As long as they aren't actually dumb enough to think they can be both and or neither genders, or switch between genders on a whim, I will. Because those people are just.. UUUUUGH.