Could my stepson be a ?

I got engaged last month and I moved in with my girlfriend. She has a 15 year old son from a previous marriage and I am very worried about him. He looks so androgynous that it is really difficult to tell if he is a boy or a girl by looking at him only. He has small shoulders and a soft, feminine face (plus long hair). I also think his waist is a bit wide for a boy. He does not have many friends. Just two close friends (a boy and a girl). He has a pet snail that he loves very much and he spends most of the time in front of the computer. He has a very high pitched voice for a 15 year old. He is a very admirable boy who is doing well in school etc. but I am worried about him. Should I ask him if he is a ? Should I ask my girlfriend if he is one? I am very nervous about asking that question and I don't want to make a fool out of myself.