It is not at all unlikely that a fairly advanced (meaning it has survived awhile and evolved over many generations) would have a basic physiological structure similar to our own.

They might be physiologically identical but they still wouldn't be human. The anythropomorphic conceit here (essential to sci-fi) is to assume that all we'd have to do to be able to talk to them is translate our respective languages.

Otherwise, that equation, like SETI itself, is the stuff of fantasy.