Why are sex content restricted to adult only?

Well theres a difference in the sex one would have with their girlfriend or boyfriend compared to the sex that would be shown in adult media. Adult media is basically mindless humping with generally no emotional connection, and is often un protected. This isn't what would want to be portrayed to young minds as the norm. Also, by putting an age restriction on it, it seems that they (who sets the limit) wants teens to find sex for themselves rather that it be seen on a computer screen or tv.

To be quite honest, the whole age limit i think is stupid since most teens generally have their first sexual encounter at around the age of 16/17 however since free porn is so readily available its extremely hard to believe that they have never seen it before. Frankly, sheltering teens from this is an act of futility since they will have most likely already seen it and ultimately sex is basically inevitable so trying to keep it from them will only fuel the desire to have it.

Thats about the only philosophical way I could explain it however, the more realistic reason for the 18+ restriction is because all actors must be over the age of 18 and so it would only make sense to restrict the age of the viewer to the same minimum age of the actor's in question.

To anybody that feels its necessary to censor this from our youth, ask yourself this. When a teen, whether its your kid or someone else's, do you really know what it going on in their room at night or on the computers when your not home? The simple answer is no, its literally impossible to monitor the youth at all times and kids are generally smart enough to delete browser history are parents generally not technically inclined enough to find the permanent keystrokes. It for this reason that everyone needs to back off and let nature take its course. Yes, its natural for teens, specifically boys, to want to discover this at a very young age but theres nothing anyone can do to prevent this.

Yes it matters. Children are still developing and although you feel like adults as teenagers, the older you get the more you realise you still have a lot to learn, and teenagers are easily influenced/led. It's part of growing up, being irrational and selfish. Although teens know about sex, and get horny, they do not have the right mindest to cope with the psychological impacts.

There was a case recently of a 12yr old boy who was found guilty of raping a 9yr old girl. He'd been watching hard core porn online and said he wanted to feel grown up.

Yes, it really matters. Teenagers are still developing mentally. There are adults that would take advantage of young teens, and we need to do what we can to protect them. Not only that, but sex comes with risks, including pregnancy and disease. Most teenagers are not mentally or emotionally ready to handle parenthood, STD's, or even just the act of sex itself.

Measuring time is a man-made thing, therefore it's really stupid to restrict something to someone based on that alone.

It's because the government want to censor everything.