What does 'what's a boy to do' mean?

Question

It doesn't even sound grammatically correct, does it?

Answer 1

It's a rhetorical question, said by a boy, meaning "What should (can) I do?". An answer is not really expected.

A girl would say "What's a girl to do?"

Answer 2

It isn't meant to be grammatically correct. It is more of an expression, used when confronted with many confusing situations and/or choices in life, one might throw up their hands and say, "What's a boy to do?" Sometimes life comes at you kind of fast!!

Answer 3

Well, it's sort of an obscure way of saying "What should/can a boy do (given the circumstances or in response to the circumstances)?" I think it is grammatically correct, it's just a construction that isn't commonly used. The contraction makes it sound even weirder, though.