This column's raison d'etre is to grumble about all the signs that tell us our youth is slipping by: the discovery of new places where hair can grow and pain can be felt; the surrendering of the Young Person's railcard and the accrual, by way of compensation, of a whole pack of bank cards, work ID cards and Tesco Clubcards.

But to be a twentysomething isn't just about being a responsible adult: half of the irritations of being a teenager are still hanging around, too. For example: spots. When do they go away, exactly? Hairless and crow's feet would be lot easier to take if we could at least say we'd put acne behind us once and for all.

Another hormone-related matter, and indeed the topic I've been psyching myself up to broach, is this. Traditionally, boys of 14 or 15 are laughed at in books and films because their testosterone is going volcanic. Powers of speech disabled by the sight of a female's shoulder blade, 40 minutes of Othello exegesis obliterated by a pencil skirt three desks away in a GCSE English class... you know the sort of thing.

Well, I'm more of a 15-year-old now than I was at 15. I'm much more of a lech, much more of a superficial, slavering, panting gawper than I ever was a decade ago (all in a very restrained, middle-classed sort of way, I hasten to add. To the untrained eye I appear relatively normal). Either Gregory's Girl was lying to me, or I have a serious problem.

Male friends have reassured me that I'm not a tragic pervert who should be manacled to the wall of a remote dungeon for the benefit of society - or rather, they've reassured me that I am a tragic pervert who should be manacled to the wall of a remote dungeon for the benefit of society, but not to worry because they are, too. We've had long confessional conversations on the subject, conversations which would, admittedly, be a great deal shorter if we didn't pause mid-sentence, mid-word even, every time a woman under the age of 70 strayed into our line of sight, only for us to pick up where we left off a minute later, with no need for comment or explanation.

"Maybe it's just the summer, what with all those shorts and strappy, vesty things," I suggested to one fellow sufferer. "No," he said firmly. "Winter is worse. In summer, everything's there to see. In winter, your imagination takes over." I wasn't sure whether to feel comforted or a little frightened.

The one question my friends could not answer was when this seismic hormonal activity is due to subside. Have we reached the peak of an arrested adolescence, or is this how being a grown-up male will always be? Does our brainless and morally compromised state intensify through the decades, until at some point in our Nineties it all gets too much for our fragile frames and we explode? I dread to think.

Meanwhile, I'm a dirty young man, and that's not a laddish boast. I realise that female readers may find the revelation distasteful. I'm not proud of the number of hours during which my mind sinks to the lurid, anatomically obsessed level of a Toni Braxton video. I just felt you should know the truth.

Coming soon: other articles you can write in a national newspaper which are guaranteed to annoy and humiliate your girlfriend.