Unidentifiable Genders

I was walking down the hall when I dropped my binder and books. This really nice kid came up and picked them up for me. I thanked the person, but I’d really like to know whether it was a boy or a girl. They had shoulder-length straight hair, saggy pants and an oversized hoodie (so you can’t tell from the body), and a face that could go either way. It’s driving me nuts.