kids are naturally curious. i dont think its abnormal at all. same thing as a young boy playing with a doll. I think the best thing would be to let him explore, just my opinion. i think more harm comes from forcing a boy to be a typical boy than just letting him explore. Would it bother you if it was something deeper? personally, i think much more comes out of holding back urges than just exploring them. then again i have been called a "damn dirty hippie" lol.