We are becoming a nation of older mothers. The average age at which a woman has her first child is now 30, a fifth reach 45 without having a baby and the usual busybodies are in a flap. The government, which had anyway decided on compulsory relationship classes, thinks the answer lies in more of the same. If we only explain to 11-year-olds how hard it is to conceive at 40, the creep towards geriatric motherhood can be reversed. Expect your small daughter to bring home fertility awareness posters designed in PSHE, perhaps papier-mâché models of a deteriorating human egg.

The busybodies aren’t wrong to worry. I first set about trying for a family just as youth was crumbling into middle-age and it was a very boring business. Three years of blood tests, referrals, Harley Street; an endless uncapping of Mont Blanc pens and popping of pills. But in the end, my son.

I’m all for sparing future generations this sort of expensive angst, but the more I look about, the more I’m sure the government has it quite wrong about the causes of late motherhood. Girls aren’t clueless about biology. The very same study (by the Fertility Education Initiative) that set off the fuss, also reported that most young people, nine out of ten of them, are already well aware that it’s trickier to conceive over 30.

Nor do I buy the usual millennial complaint that they don’t earn enough to support a family. That FEI study found that most women, whatever their income, are keen to have kids before they turn 30.

I hate to kick men when they’re down, ducked beneath the parapet for fear of angry feminists, but I suspect the real problem here isn’t ignorant girls but unwilling boys.

I have several female friends in their early thirties who’ve wanted a baby for a while. Ninety-five per cent of girls do, says the FEI. The trouble for them hasn’t been the cost of childcare or a demanding career. The trouble has been finding a man who’s even halfway keen to settle down.

All my pals looking for Mr Right report identical patterns of behaviour. Dating is now all online. So they scroll through endless profiles and eventually make contact with a promising guy. Cue weeks of pointless text-ing followed eventually by an actual date. The evening often goes well. There might be a snog, more texting and another date arranged. After that: nothing. The promising man, who’s caught wind of a woman with family plans, submerges back into the internet to scroll through the options again. Why commit when Kate Moss might be beckoning from behind the next screen? It’s so much easier to imagine someone’s perfect when you haven’t yet met them.

If online dating turns more men into commitment-phobes, I don’t see why anyone should be surprised. It’s women for the most part who feel the urge to nest and breed — as we all once quite freely acknowledged before gender became a choice. Most men don’t feel the same need to play house. It took the threat of public shame, fear of God and the censorious tutting of mutual friends to chivy a man towards family life. Online, dating strangers, who’s to see or care?

A decade ago, when I was single, I was often kindly set up by my married friends. Among the men on offer was a very particular type of feckless lothario left over from the half-generation ahead, who’d run though the girls in their peer group and were starting on the next lot down. They were handsome in a worn way and image-conscious. They wore trainers with suits, played guitar, and a wise girl steered well clear. These were men who’d been teenage golden boys with their pick of chicks. They’d never grown out of self-absorption, because, I suppose, they’d never had to. Any girl foolish enough to get involved was pulled into orbit around the narcissist, into endless conversations about their progress in life, their neuroses, the meaning of their dreams. The girls imagined they could eventually persuade them to have children. They never could.

Where I live, on the fault line between Islington and Hackney, the coffee shops are full of young people, of perfect breeding age according to the FEI, discussing their lives. I sit spider-like and listen, and I’ve found to my slight horror that all the hallmarks of the old feckless narcissist are present in more than half the men I overhear. There’s the over-concern with grooming: hair, beard, tattoos. Then, after they’ve arranged their avocado egg toast and photographed it for Instagram, the endless talk about themselves. They begin: ‘The thing about me is…’ Then there’s no stopping them.

Last summer I listened to a good-looking man of 30 talk for over an hour to an older chap who turned out to be his life coach. Our hero wasn’t happy, he said, but why? He’d tried every self-improvement fad going. He had a therapist, a personal trainer, a NutriBullet; he’d downloaded the headspace app… What could be wrong? Why not settle down, said the life coach, have kids? Well, he’d tried, said the man, but every time he looked at his girlfriend he began to agonise over whether she was good enough for him. He’d discussed it at length with her, he said, but he just couldn’t make himself commit. ‘I think the answer is to cut the negativity out of your life,’ said the coach, nodding sympathetically. ‘Do something just for you.’

I have an idea for the new relationship classes. I think it’s a winner. Girls from eight years old, say, should be asked to create a public awareness campaign in PSHE: how to spot a commitment-phobic narcissist.

Then posters on the tube maybe: ‘Run. Hide. Tell.’ I genuinely think the government should consider it.