I just want to comment further on this because it's not clear what your feelings are about having a homosexual child - this implies you may be in denial: I'd echo all of what /u/47TheRealAnswer and /u/WhackAMoleE had to say.
Dan Savage has had several good columns on the topic.
If you are unsure about how to talk to him, start reading up. This may seem uncomfortable, but he clearly needs to have this talk with you. You need to talk to him about what the possible risks are in flirting with or having relationships with older men. He is 15, horny, and new to the world of sex. Next, you need to have a larger conversation with your son about his sexuality. out of your son's room and tell him that he may no longer use them in his room alone. I would recommend taking the computer, phone, etc. All it takes is for one of these guys he has been chatting with and it comes back to your, your son, and your home. You need to have an immediate conversation with your son, explaining that his behavior is illegal and places his/your family at HUGE risk for felony charges. As the adult who is legally responsible for the home and its contents, you are now also the owner of child pornography. Your son is making and distributing child pornography. I'm not sure how to explain to him that it's not ok to do that with pedophiles online. I'm worried that he's been doing this for a while. I'm not worried that he's gay or anything, everyone has their fantasies. He had Imgur open and was in the middle of taking the picture when I walked in. It doesn't look like he sent any pictures, but he was certainly going to. The men were all 33 - 46, some were in their 20s. He was wondering if they could do it more often, say when the other guy is horny he could send him a message on Skype asking if he was interested, and then he'd do everything that the guy told him to do. He asked them to make him their bitch, and he talked about how it makes him horny to think about being made a sissy by older (27+) men. There were tons of private chats with him saying he was 15, and that he liked older men 27+. I looked through the tabs and he had tons of gay chat rooms open, with usernames saying he was 15. I looked at his browser and he had tons of tabs open with gay chat rooms. A man was masturbating on a Skype call (fake account) but he was not on cam himself. I walked in and he was on his bed taking a picture of his penis with a timestamp. Unfortunately, people who feel rejected can try to get revenge by posting personal things you've said or photos you've sent online.My son is only 15 and last night at around 12 AM I woke up because I heard something from my son's room. Never say, do, or post anything online that you wouldn't want the whole world, including your parents, to see.If your gut instinct tells you that somebody is creepy, trust it and move on to someone else.Do not ever arrange to meet someone outside of the chat room.That includes your last name, where you go to school, the neighborhood you live in, or anything else that someone can use to locate you. Use these tips and ask for help when in doubt to maximize your online security while in a chat room. Even if you feel like an adult who always makes responsible decisions (and even then, no adults can honestly make that claim), there are a lot of potential complications to flirting with strangers. You need to keep yourself safe while online.
You've heard it before, and you are about to hear it again. Always Keep Safety in Mind on Teenage Chatting Sites