Honesty, honesty, honesty. Let him know you are aware (without totally embarrassing him). Let him know that at 12, even though they think they are totally grown up and ready for that type of viewing that they really aren't, and it's something you and dad don't want him doing, and won't allow. I would especially be concerned with him lying about his age on the site. Also regularly check the site, to see if there are anymore current visits. I'm a grandma to 9 children now, 8 of them boys, and had 3 boys myself. What makes you think at 12 that he isn't going through puberty? Most boys have already began puberty at 10-11, and by 12 are pretty well through some of it. I actually caught my oldest son at 11 (I won't type it out, but it begins with a M) in his room. He was devastated when I walked in. My twin grandsons who just turned 13, have definitely gone through puberty. It might be a basis to start a conversation, such as "I know you're beginning to have different feelings, and curiosity, but..." and I would suggest dad be the one to have the conversation with him, since he could share how he felt at the same age. I know this isn't the best advice, but hope it helps in some way. You don't want him to feel like he's weird for having done that, but you need to make him know it's not ok to be viewing that kind of thing on the computer. It's sooo normal for boys that age.