So will Coronation Street commercial breaks now be filled, as Conservative MP Nadine Dorries fears, with vignettes of “pretty nurses, gleaming reception areas and leafy car parks”, perhaps concluding with a smarmy white-coated doctor declaring “We're the best - for all your abortion needs”?

Unlikely really, since the response of Marie Stopes and other sexual health clinics to the proposed review of rules that may permit them to advertise on prime-time TV was pleased but doubtful. Yes, interesting idea, nice if we could afford it, but we are only charities. Given the fragmented nature of the multichannel age, a brief slot on a youth-orientated music station might be the best use of funds. And would this be so wrong? Even if an ad did highlight the care, safety and compassion with which an unwanted pregnancy is terminated these days, would that matter if it reassured a few desperate, terrified girls?

Never mind. It won't happen. Such ads as may be permitted will be no more than discreet offers of counselling for the worried and phone numbers to call. The very same copy has been running in Tube stations and the back pages of women's magazines since reproductive rights were won. It won't be, as the moralists froth, the “abortion industry” cynically marketed by Mad Men.

Since Britain's stubborn and shameful teen pregnancy rate increased again this year, one feels that the Government is now lobbing everything it has left to reach its targets by 2010. And the 40,000 girls under 18 a year who get pregnant are not - contrary to myth - all lowlife scum pushing out a baby to bagsy a council flat. The number of births to teenage girls has declined since the 1990s. It is abortions that have risen, and so one must conclude that the last thing that these girls intended was getting knocked up.

So let's cautiously welcome the new prime-time ads for condoms and sexual advice clinics, however embarrassing they may be when watching with your ten-year-old, whatever the squirm-making questions provoked, all your pretty notions of childhood innocence blown away. Because, damn it, we are not Dutch. We are a smutty, furtive nation, not a frank, unblushing one. And no pre-watershed dancing Durex ads will ever change that.

Yet let the Government also promote another campaign. Aim it at teenage girls. Call it “Are you sure this is what you want?” Indeed, the editor of teen mag Sugar, Annabel Brog, who reads the gel-penned missives of thousands of girls every year, has a better slogan: “You'll never regret not doing it.” If you're uncertain, just stop: he's a teenage lad, there's no way he won't ask again!

It is risky, provoking accusations of prudery and fun-sucking, when feminists venture towards the concept of abstinence. But that is not what I am preaching. If, in the years since I was myself a hormonal loon, girls had intrinsically changed, become more assured in their sexuality at a far younger age than me and my Cathy-and-Claire-reading mates were, I would say, go forth and copulate - just be careful.

But I don't believe that to be true. Girls are programmed to please; more vulnerable than boys to the opinions of others; more eager to fulfil prevailing expectations. When being brainy was deemed unfeminine, they underachieved; now that getting 10 A*s is cool, they excel. When being drunk was unladylike, they stayed on their feet. It is not a hitherto repressed thirst for liquor that makes teenage girls now three times more likely than boys to be treated for alcoholic poisoning, but the fashionable notion that they should love to party.

And the model of a raunchy, perpetually up-for-it hottie that is thrust at them through reality TV, celebrity mags and the internet is no more a manifestation of their inner desires than a dirndled Fifties virgin. Yet if this is what being Ms Teen 2009 entails, they will vie for the title. A women's glossy magazine rang me this week about a survey showing that female twentysomethings now seek out one-night stands as readily as any man. Wasn't this, I was asked, magnificently empowered? Only, I had to demur, if it's what they really really want.

Are the American high school girls taking part in oral-sex contests, girls who send snaps of their breasts to be assessed on lads-mag websites, the 15-year-old girls having unprotected sex also empowered? Isn't it just too much of a coincidence that these images of supposed liberated female sexuality just happen to mirror male fantasies?

Shame, fear and a horror of being thought a slag used to stop girls having sex. They weren't great excuses and often little impediment. But they were flags to wave when girls really meant “I'm not ready”. Now even “I don't want to” isn't enough when fashion dictates that a girl must appear to want to, all the time.

If only we could truly empower girls, help them to distinguish between desire and coercion, show them how - without losing face - it is possible to say no. Government campaigns can blanket-bomb British adolescents and deluge them in condoms, but they will not reach inside their hearts. Brog says that she detects in her readers “a desire that their parents be parents again”. Watching Sex and the City with your 12-year-old, as though you are mates, is just not enough.

And when the hardest-core porn is just a click away, when teenage boys are raised on Nuts and Zoo and 13-year-old girls on Facebook pout and pose and play with their new-found power, the old parental sex talk must be stepped up to a PowerPoint presentation.

Who has the stomach or the nerve to guide kids through a newly sexualised culture that shocks and dismays even the Sixties-born? And so the rules are being redrafted, irksome details worked through. Many parents even allow their children to sleep with teenage partners at home.

Governing your children's sex lives can be an ugly process, as Julie Myerson reveals with awful candour in The Lost Child, as she all but frogmarched a girl impregnated by her skunk-smoking son down to Marie Stopes. The girl's own parents were too weak and flummoxed to act. And it is for the sake of those such as her that we will all have to sit, teeth-gritted, watching the new commercials.

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