Children are naturally rebellious. They do not realize the potential repercussions of this movement, though.
Thus, they should be reined in, as they had been in the past. Then came the post-modern movements, the internet, the behemoth of giant corporatism, dissolution of the nuclear family, and so many other ills of post-modernity.
Many parents nowadays have abdicated and simply allow their children free rein while they look on from within the confines of an alcoholic or drug-induced haze (prescription or otherwise). Other parents simply abandon their children to mass media, video games, and a broken educational system that no longer educates, but only indoctrinates.
My son grew up with the internet. When he was about 10 years old, he left some "evidence" on my computer of a gay pornography site. I knew he had left that evidence, and I very calmly confronted him about it--and explained very kindly and in a way that he (as a 10 year old) could understand the harm it could cause him and why he must never "go there" (or to any other pornography.) I suppose it was our "birds and bees" moment.
He is now 31 and a happy, well-adjusted hetero adult male who makes well over six figures. I'm very proud of him and glad we had that talk so long ago. It is a pity that very very few parents now will ever talk with their children like that. Which is another reason why.