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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If it's guy wanting to be a chick I will call him a he until he gets the surgery, until you cut off your cock your a He, and ladies wanting to be dudes need to have a duck before I call them he, my point is my pronoun depends on the parts you currently have