male/female?

One of the things I do is interview applicants to a prestigious university. The other day, I had a very odd experience: I interviewed a student who gave off very conflicting gender signals. On the one hand, they had long hair, a female name, certain feminine secondary sexual characteristics, and referred to themselves as a girl. On the other hand, there was something about their voice that, every time I heard it, made me think "this is a prepubescent boy in front of me." It was a very odd experience. I kept on wondering if I would have categorized the student and their attitude differently if I had been sure of their gender, one way or the other; if I would have seen their cheerful, happy attitude differently if I were sure they were a boy, or a girl. It was pretty distracting, actually.