The Daily Telegraph's Allison Pearson recently wrote a deeply troubling column recounting how she and female friends had discussed the challenges of parenting teenagers in the age of internet pornography.
The consensus was that it's a tricky if not problematical business. The dissenting voice was that of a GP who works in a salubrious suburb. "I'm afraid," said the GP, "things are much worse than the public suspects."
She's treating growing numbers of teenage girls, often under the age of consent, with internal injuries caused by anal sex. The girls find it humiliating and obviously painful but their boyfriends, taking their lead from pornography, expect it of them. Many parents are unaware of the real reason their daughters are going to the doctor.
The moral of the story, says Pearson, is that "internet porn has changed the landscape of adolescence beyond recognition".
Research supports this anecdotal evidence. A Europe-wide poll found 40 per cent of girls aged between 13 and 17 had been coerced into sex acts. A study by two UK universities found a high percentage of teenage boys regularly view pornography and one in five has "extremely negative attitudes to women".
A paradox of modern life is that the rise of feminism and consequent focus on sexism in public discourse and everyday life - witness the furore over John Key's ponytail-pulling - has coincided with the rise of pornography which objectifies women. Actually, it goes further than that. Pornography's core narrative is that there are two types of women: nymphomaniacs and those who haven't yet realised they're nymphomaniacs but are about to have a light bulb moment.
Furthermore, pornography's raison d'tre, like that of horror, is titillation. Because potency is measured by the degree of arousal generated, both are obliged to push the boundaries of explicitness and abnormality. In practice this means a couple engaging in vanilla sexual activity barely qualifies as entry level porn.
Conservatives have long argued that mass immigration was an uncontrolled - and undemocratic, since the public never really had a say in the matter - experiment with unforeseen and largely negative consequences. We're familiar with the predictions that Europe will be predominantly Muslim at some point in the not too distant future. Much of it is scaremongering: more careful and scientific assessments indicate that by 2050 one in 10 Europeans will be Muslim. Most Europeans may well be quite comfortable with that, but it's legitimate to wonder whether the politicians and civil servants who set the wheels in motion foresaw that outcome.
One suspects they were thinking five rather than 50 years down the track and didn't lose much sleep over the long-term consequences of their social engineering.
You could say the same about pornography. It seems safe to assume that those who made the decision to effectively abandon the censorship of sexual material didn't anticipate children would have devices that allow them to view porn at the press of a button or a vast, global communication and information sharing technology that enables the mass distribution of free porn. (Conventional wisdom has it that 30 per cent of all data transferred across the internet is pornographic.)
In three decades pornography has gone from a furtive black market to big business: bigger, indeed, than Hollywood. While there's still a slight stigma attached to consumption, porn's pervasive influence is unchallenged and its stars are showbiz celebrities. And now we are starting to see the unforeseen and unintended consequences.
According to Dame Esther Rantzen, founder of the National Society for the Prevention of Cruelty to Children's ChildLine service, "young people are turning to the internet to learn about sex and relationships".
What they'll learn from pornography is that relationships are just a matter of physical proximity. Porn doesn't do relationships - it skips all that getting to know, falling in love stuff because no one views porn to watch people gaze into each other's eyes.
Porn is anti-love since love leads to monogamy, and where's the fun in that? Who wants to be limited to one body when there are all those appendages and orifices out there?
If teenagers are getting their life lessons from porn, then we're not merely contemplating the end of innocence, we're contemplating the end of romance.