Is this abnormal behavior? He loves sports and has had girlfriends. I'm just not sure how to handle this and I don't want to tell his father because I'm not sure how he would react. Should I confront him with this or just ignore it? Does this mean something about his sexual orientation?
He may unconsciously want you to catch him in this cross-dressing as he has taken your clothing and your shoes, articles that you certainly would notice were missing. He also left these articles of clothing in view of anyone who came into his room and happened to look into his open drawer. An alternative explanation is that his cross-dressing has become somewhat of an obsession and that this has prevented him from thinking logically about his being discovered.
Most adult cross-dressing males began seriously cross-dressing in their early adolescence. Most cross-dressers are heterosexual. The behavior is harmless, except when this obsession becomes a problem in a relationship or in a family.
Bring up the subject with your son, referring to your missing articles of clothing that you saw in his drawer. Ask him why he took them from you without your permission and, before he begins to lie to you out of shame, rhetorically ask him if he was dressing up in your clothing like he used to do when he was younger. Please do not blame him for this behavior. Tell him that you realize that this must be a very strong urge in him to make him take your clothes and lock his door. Explain that many boys engage in this behavior, which is true, and that most of these boys do it in secret as he is.
Get the names of some sexologist-therapists in your area, experienced therapists who have treated adolescent cross-dressers. Your son is sending up red flags to you that he can't handle his cross-dressing urges. Because of his other activities, it's understandable that he wouldn't want to appear as anything less than a "macho" young boy. Tell him that you are going to help him get the help that he needs so that he will not be so troubled by this behavior. Don't keep this secret from his father because family secrets like this always have a way of bringing more pain than less into the life of the family. Please caution your husband that he could severely harm your son's fragile emotional well-being if he in any way shames him after learning why he was in therapy. I know that you will get your son the professional help that you need.