On the subject of diagnosis, if there is a component of autism, it could account for a level of perseverative behaviour in this that can be really scary if you don't know where it is coming form. Autism Spectrum Disorders (ASD) kids can pick up habits after one experience of something. An example I give is - we go to the beach often in summer. We go to the beach by car, we drive home by car. The beach is five minutes away. ONE TIME I stopped at the local shop to buy milk (as I sometimes do) and decided, on impulse (since it was a hot day) to buy the kids an ice cream. From that time on, every time we were leaving the beach, difficult child 3 would insist on an ice cream "because we always get one". Even though I never bought an ice cream after the beach again, the tantrums and tears continued for several years. We dealt with it by buying inexpensive tube ice blocks and letting him have one of those at home after a beach visit.
Next point - curiosity about porn is normal for boys, as a rule. We found with difficult child 1 that his friends would show him porn (travelling to and from school) and we would often find various porn magazines in his room or in his school bag. The day he got suspended his bag was searched and a very crumpled soft porn magazine was found in the compost in the bottom of his bag. The acting principal was on thin ice with her discipline of difficult child 1 and was trying to use the presence of the porn to get me outraged at my son, in order to distract me from the main issues. Instead I closely examined the porn (with easy child, who was 19 years old - difficult child 1 was 17 at the time) and pointed out where it had been airbrushed to hide things like pubic hair etc. I did not let the teacher get away with this method of trying to distract me.
BUT when I got home, I talked to difficult child 1 about porn. I followed some of the methods already suggested - sex education, basically. Which in our family is not just about the mechanics of how babies are made, it is about sexual responsibility. That includes emotional responsibility and compassion/consideration for one's partner.
Then I went in to educate difficult child 1 about porn. I did this by sitting with him and looking up porn online, but from a different angle. You need to be able to hide your own revulsion at this, do not do this if you can't avoid being judgemental. A good way to begin is to Google "dead porn stars". There are a number of websites that give a history of porn and especially porn stars. Some survive and get to enjoy their earnings, but they are a minority. The women especially have very short, unpleasant careers, the industry chew them up and spits them back out (as unusable by anything) in a very short time. Again, there are a few exceptions. The reasons a person takes up a career in porn is wildly variable and this also has a bearing on what happens to them. For example, a girl who 'falls into' a porn career out of financial necessity (a runaway, a kid who left home to escape sexual abuse then finds herself on the streets as a prostitute can see porn films as a means of escape to a better life - it's not) or out of drug addiction, generally becomes a statistic. Look up the life stories of these women. Look at their backgrounds. If you think about it, the sort of girl who gets abused by this, manipulated by this and destroyed by this has often already been a victim before the porn industry finds her. Or she could be a decent kid who thinks this is a fast way to make a bit of money, but doesn't realise the emotional damage this can do to her. Engage your son in their human stories. Also, the process of making porn, the photographic tricks, the way the sex act has to be displayed (so they're actually not having sex normally, but in some weird position that lets the cameras in for a closeup) is far from natural, or a reflection of what is normal.
Teach him about normal sex. Also make it clear that this is what people do when they find someone they really care about who also wants to have sex with them. Sex under any other circumstances is just plain wrong, and also personally damaging. It really does do a lot of damage to have sex, or force sex upon someone, when it's not really wanted or either individual is not ready for it.
The point of all this is - porn, in general, is unnatural. Wanting to look at it IS natural (especially for boys) but they need to learn that there are people being exploited in this stuff, it is so close to rape it is not funny. When you choose to have sex because it's that or starve (or suffer severe drug withdrawal because you can't afford your next fix) then it is as coercive as having sex while someone holds a knife to your throat.
Sex is supposed to be something special and beautiful. Porn is the opposite. What it does to people is appalling.
By me sitting beside my son (not his dad, but me) it made it even more personal for him and showed him that I was not going to be horrified by the bare flesh, although I was able to be horrified and distressed by the poor people (male and female) who died young because of their involvement. It also directly led the way for me to teach sexual responsibility. of course I wanted my kids to wait until they were married before they had sex - that is an ideal that these days is frankly unrealistic. If you are strict enough about this, you think, then your children will stay chaste.
Don't you believe it. All you will do by refusing to acknowledge the possibility, is drive it underground. We have friends at church whose daughters used to climb out of the bedroom windows at night. They drank, used drugs and slept around. The parents still don't know and if I tried to tell them, they would refuse to hear it. I know, because another friend from church has a daughter the same age and the girls used to talk to one another.
Interestingly, when easy child was living with SIL1 before marriage (not even engaged) I had a church elder approach me to ask me how I could condone this. I pointed out that easy child was an adult who made her own choices, after having been raised in a Christian environment. I said that SIL1 is a young man whose presence in our family we value. Yes, I would prefer them to be married, but SIL1 had a lot of emotional baggage on the subject of marriage and Christianity and frankly, the best thing we could do for him was to undo the damage by loving him, being welcoming and showing him that not all Christians will treat him badly simply because his mother was abandoned by his father (ironically, a religious man) when she became pregnant. It took some years but SIL1 did eventually freely propose marriage and they are very happy indeed, have just had their second wedding anniversary and are now expecting their first baby. If we had imposed our wills, it would have done nothing for his healing, and could have driven a wedge between us and our daughter. He could have felt forced into marriage and resentful. Now? He is learning to value marriage and respect our beliefs.
Interestingly, when that same church elder's children became sexually active, he shut up about the issue!
You can't win with prohibition. If your child has any similarity to Autism Spectrum Disorders (ASD), then prohibition will never be sufficient to overcome the intense drive to do what he wants to do or feels is right. A better way its to shine a searchlight on the issue and re-educate.
We also grossed out our kids by taking them shopping for condoms (as part of my campaign to teach sexual responsibility). In Australia we can buy condoms in the supermarkets, they are next to deodorants. I did not lower my voice in any way, I pointed out which brands to avoid, told them to not get too intrigued with flavoured condoms because they are very chemical in taste and frankly the banana ones especially are awful; I told them to not bother with "ribbed for her pleasure" because a vagina doesn't have sensitive enough nerve endings to feel the difference, and those ones can reduce the pleasure for the man because the condoms tend to be thicker. My knowledge on the topic I am sure, bought us another few years of celibacy in our kids!
Other than that - monitor it. Try to insist on some level of supervision at school, if tey insist that WiFi cannot be turned off (which is a ridiculous statement, frankly).
And if possible, try to find something else to engage him. difficult child 3 is currently caught up with 3-D photography, he takes photos on his Nintendo 3DS and processes them through the computer into a monochrome form that can be viewed online with red/blue glasses. There are also online social groups that have strict rules about online behaviour, but are a lot of fun for a kid. difficult child 3 is slowly learning some important social rules on a few of these sites. I encourage him to talk to me about them, he has sometimes asked me for help with a conversation. He has learned the rules (belatedly - he has nearly been banned a few times for inappropriate language when someone upset him) and is now quick to blow the whistle on inappropriate behaviour that breaches the site rules. Have a look at the sites first. Gaia is one I would suggest you look at.
We live in a modern world and increasingly, internet connectedness is a part of life. We need to teach our children to use it wisely and appropriately. Prohibition is a last resort that is a lot of hard work and can still often fail spectacularly.
You may have more success controlling his access to his 'friends'. When difficult child 1 was 14, his friends (the ones who were supplying him with porn magazines) were a bad lot. One kid was okay, but he soon stopped being okay when he got hooked in to the dark side. He is also an Aspie (like difficult child 1) but this just made him more vulnerable to manipulation by the kids he wanted as friends. difficult child 1 survived this stage because he had a strong sense of justice and right/wrong. We worked hard to keep this on track with regular (many times daily) social skills lessons. Every opportunity, we taught the natural consequences to others as well as ourselves, of breaking the rules. it is a facet of Asperger's which we shamelessly exploited.
Your son gets very tired - if he is putting in a lot of effort during his days (and I often describe this as the swan on the lake - it looks serene and relaxed but there is a lot of furious activity going on beneath the surface of the water to make this possible) then this will make him very tired.
You need to become his facilitator and not his obstacle (from his point of view). It is natural when you have a child like this, to clamp down more and more on controlling him, when his behaviour is so challenging. But with some kids, it is this very tightening of controls that can make their behaviour worse. You end up becoming a jail warder and life loses its fun for you and for him. There is only one direction to go from here and that is downhill.
On this site we recommend "The Explosive Child" by Ross Greene. read it, it might help you find a better way to reach your son and help him understand that you love him, you want him to live right and you are there to help him learn how to be a healthy, happy, productive, independent adult. It's never too early to start, in making a start in areas you can trust him with, you can begin to let him see that your aims and his do not have to be in conflict.
Marg