Please help me. Is my son possibly gay?

He has recently plastered his bedroom walls with posters of Lady Gaga, and he even has a mannequin dressed up like her.. shiny clothes, big sungles, blonde wig and everything. I hear him occasionally talking to the mannequin. I walked in his room last night to ask him if he wanted a snack and I caught him singing that "Born this way" song into a purple . He does like going to the mall and never talks about a girlfriend or any girl for that matter...is he gay? He is 22.