I always thought that was a pretty awkward line. Like who actually asks that and what the hell is it even supposed to mean?
Technically, the only time the answer to this question would be a definitive "No" is if you're asexual. Otherwise, it's like asking "Am I A Person?" - yes, you are, and a very annoying one at that.
If your sexual urges have got you confused, here's a handy guide on 101 ways to say no