Anyone who asks me "Is that a guy or a girl?" is almost certainly going to get one of the following three answers: Yes; No; Why do you want to know?
Addendum: Part of what I was thinking [and didn't say] is that, unless the person is asking about a young child (or a dog, cat, or other non-human), I'd be wondering "why are you asking me? Why not ask the person directly?" [If I'm out and about as the caretaker of a young child, of course you'd ask me, along with things like "how old is s/he?"
Also, the appropriate pronoun for talking to someone you meet is, in English at least, not gendered: "you" covers singular and plural, of any genders.
Addendum: Part of what I was thinking [and didn't say] is that, unless the person is asking about a young child (or a dog, cat, or other non-human), I'd be wondering "why are you asking me? Why not ask the person directly?" [If I'm out and about as the caretaker of a young child, of course you'd ask me, along with things like "how old is s/he?"
Also, the appropriate pronoun for talking to someone you meet is, in English at least, not gendered: "you" covers singular and plural, of any genders.