I was complaining half-heartedly to a friend about the gaggle of boys that roams around my house every school holiday — I mean my sons and their friends, not random teenagers off the street, though there is occasionally some overlap — and she pointed out that in another five years I’d be sending the eldest off on his gap year and would have a lovely peaceful few months ahead, with only the threat of kidnap or loss of marbles through excessive pot-smoking to worry about.

I was just digesting this when I discovered that Mary Killen, The Spectator’s estimable agony aunt, had written about how gap years were really just an excuse to get your parents to cough up for you to faff about on some beach with your mates, in the name of horizon-broadening. Killen’s point was that so many children take gap years with their friends that the idea of them meeting anyone new, let alone anyone from a different culture, is risible, and that all gap years do is re-create a Saturday night in Chelsea, Wiltshire or wherever, except with better sunsets, less supervision and more drugs.

Gap years started because sitting the Oxbridge entrance exams used to involve an extra term at school, leaving one with a spare nine months. Now that Oxbridge entrance happens at the same time as ordinary entrance exams, that excuse is gone — and yet gap years have gone from strength to strength, regardless of which university you’re headed for: many teenagers see them as the norm.

Twenty-odd years ago, I spent my gap year first waitressing and then pulling pints in various deeply unglamorous establishments in deeply unglamorous (at the time) Islington, north London, and although I did feel a degree of spoilt-baby resentment when I got to Cambridge and discovered that most of the people I knew had spent the previous year travelling around India/Thailand/Australia, I can’t say that I was overwhelmed by their easy manner around people from different social or ethnic backgrounds.

Au contraire: far from developing the kind of all-embracing, barrier-smashing friendliness that travel of this kind is supposed to encourage, I found that those who had shared experiences in Goa with their mates from the upper sixth were, if anything, more cliquey.

Also, incredibly tiresomely, this kind of travel bred — and presumably still breeds — a fixation with India in a certain kind of upper-middle-class girl, who’d follow bemused Asian people from Bradford around saying “Namaste” and wittering on about Ganesh and dhal. White teenagers who holidayed with their parents in a couple of Jamaica’s most exclusive super-deluxe resorts came back with a variant on the same theme, announcing themselves to be at one with the people of the townships, and developing an obsession with — at the time — reggae and goat meat.

Having said that, I do think everyone should have a gap year; it seems an entirely reasonable reward for those seemingly endless 14 years of slogging away at school. But I also think that, if the object of the exercise is the broadening of horizons, people might be more imaginative with their choices.

Pulling pints, for instance, while lacking immediate appeal, does at least have the virtue of bringing an 18-year-old person into contact with other people from other backgrounds. It always amazes me that some people manage to go through life sticking only to their “own” — boarding-school-educated men, for instance, who then go to straight to university, and then straight into a world that is also institutionalised, such as politics.

The people who gap on Thailand’s beaches tend, by and large, to be those who are relatively used to travel because their parents took them to interesting places during their childhoods. The people who’d really benefit — those with a suspicion of “abroad”, unless “abroad” does cooked breakfasts or is Ibiza — can’t afford to laze around on Mummy and Daddy’s money, and as a consequence tend perhaps to take rather an insular view of things in adulthood.

This is something of a generalisation, obviously, but it remains true that travel broadens the mind — it’s just that travel often isn’t an option for the minds that are sometimes noticeably in need of a little breadth. In an ideal world, such people would be sunning themselves in Goa and their more moneyed counterparts would have a go at working for a living, the earning of one’s own money being, to my mind, quite as thrilling as backpacking around Asia having dreamy thoughts and spending Daddy’s cash.

I also think — though perhaps this is 20 years’ worth of resentment speaking — that there is a great deal to be said for adult gap years. As we know with the luxury of retrospect, university is wasted on the young, who, understandably, tend to see it as an excuse for three years’ worth of partying, unless they are unusually diligent and self-disciplined.

I went to university reasonably clever and came out with my brain practically atrophied, having spent the intervening years running around having a laugh, and nothing else. I wish I’d paid at least some attention: I found a bundle of my old papers the other day and was saddened to realise that the chance to sit and be talked to by people who really knew their stuff was never going to come my way again, alas.

Perhaps university entrance should be delayed by a couple of years; one of those could be spent earning enough money to go gapping the next: that way, everyone would get a go and horizons would be widened in all sorts of directions, not just the obvious, privilege-friendly ones. Faffing around in the sunshine doing nothing much is underrated: everyone should get a go at it once in their life; but it is equally true that, in terms of equipping children with the social skills to get on in life, having a go at the kind of job that’s a million miles away from their stated ambitions isn’t going to do them any harm either.

• The BBC’s new three-part science series, Secrets of the Sexes, starts tonight with a promising opener called Brain Sex, which sets out to discover whether the sexes are really as equal as we’re always being told they are: with the help of experiments involving things like brain scans and a woman receiving monthly testosterone injections. The answer seems to be fairly conclusive. No.

  Opposable thumbs aside, men and women couldn’t be less alike. I urge you to watch the series, not only because it’s really interesting, but also because if you’re of my vintage, and have had the idea that men and women are exactly the same and absolutely equal in every respect drummed into you for decades, it feels incredibly refreshing to hear it said that our differences, not our alleged similarities, are what make us interesting to each other.