When children do things which not only make them and their victims old beyond their years but also place them beyond the boundaries of normal, shared experience, we all rush to unpick the Gordian knot of cause and effect.

When Jon Venables and Robert Thompson were found guilty of the murder of James Bulger, for example, it was decided that the problem lay with "video nasties", the gory and hyperbolic schlock-fests they had been allowed to watch and which had supposedly inspired their violence.

But it's terribly easy to pin the blame all too literally. In the case of the Bulger murder, there were clearly other aspects at play – such as deprivation and neglect; the horrors which unfolded had a social cause, certainly, but not necessarily a cultural one. It's far too simplistic to plot a direct correlation between the two, and say that grisly films and shoot 'em up video games make juveniles go out and copy them. After all, an overwhelming majority of children and teenagers mature and live out their lives without killing anybody.

But transplant that cultural stimulant to a more common scenario, to something most of us will inevitably end up doing – like, say, sex – and the results are very different. That a 14-year-old boy appeared in court this week for the assault and rape, two years ago, of a nine-year old girl is a case in point. His reasons for committing this crime? He watched free porn on the internet and wanted to act like a "grown-up".

So while video games might not be nurturing a future generation of killers, the profusion and preponderance of explicit online pornography may well mean an entire swathe of young boys who reach manhood with little or no understanding of what women and sex are supposed to look or feel like, whose brains and libidos have been so regularly stoved in with images of sordid violence and seedy objectification that they are numb to anything more affectionate or domestic.

That porn leads to rape is a rather linear view, although there are plenty who would agree with it. I don't go that far, but it's ridiculously naive and optimistic to think that the generation of teenage boys who have come of age with unfettered access to the sort of sexual imagery that litters the web can remain in any way unaffected by it.

Yes, men have always been a bit grotty: they have always needed visual stimulation of a sort that women don't, because they have entirely natural funny urges and have to deal with their own creaking scaffolding. But previously, they've had to cough up for their fix of cartoonish knockers and dangly bits; they've had to fumble for coins and buy it from someone who has a face and feelings. And while you might not want your mum to find those mags, there wasn't much in them that could offend the rest of us or derail young minds.

On the internet, there is. And you don't have to interact or pay for it. On the internet, people are humiliated and subjugated. They look a certain way; they don't complain; quite often, they even appear to be enjoying it. At the very best, a teenager progressing from porn to people might find himself terribly disappointed. More likely, he'll just be dreadful in bed. But in the worst-case scenario, he'll expect female partners to engage in and enjoy all manner of not particularly appealing things, while being bright orange and glabrous, with rigid and immobile breasts the size and consistency of nuclear warheads.

And the worst of it, the very worst of it, the horribly unjust and frustrating worst of it is that anyone who complains about it or raises objections, anxieties and questions is branded a prude, a retrograde social conservative. I am no Mary Whitehouse, but I do not like porn. I think it exacerbates gender inequality far beyond the bedroom. I think it creates endless interactive difficulties between men and women and, God knows, that terrain is already bumpy enough.

But porn is every man's secret shame, and they'll harrumph in self-defence and mortification until the end of time for their right to some hairy-palmed time alone in the garden shed. That isn't the issue. Do that, by all means: that is no bad thing. Just please don't watch some pouting Barbie doll get beaten up by a giant penis while you do it.

I'm not uptight. But I resent that this type of porn has become as acceptably masculine and quotidian as football and a pint of beer. I resent the way it makes women feel inadequate and shuts them out of sex. And I resent the trickle-down into every other arena, which means you can't switch the telly on without seeing someone being vigorously and gratuitously knobbed over the kitchen table. But most of all, I resent the fact that a teenage boy is made to feel he should try it out on a nine-year-old girl. Sex should be a bit of fun. Shouldn't it?

h.walker@independent.co.uk

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