Why do men never grow up?

Excellent news - the BBC has announced there is to be a new series of Men Behaving Badly. Less than excellent news - this series will feature Gary and Tony several years older.

So, are we going to see the two lovable desperadoes accepting the lukewarm embrace of middle age, engaging in passionate debate about Jordan the country rather than the, ah, model? I have high hopes that they will have resisted the call of middle age, hygiene and maturity, based on my assumption that, no matter what life changes they may have undergone, they will have remained men. And therefore, especially in each other's company, eight-year-olds.

Women find growing up less of a problem. They devote most of their childhood to practising for womanhood - tidying their Wendy Houses, reading up on pension plans. Men find the transition fraught. Granted, many post-adolescent males do manage some of the adult stuff - swapping short trousers for long, for example, or switching from Tizer to lager, even learning how to drive, occasionally under the speed limit.

But if men do acquire the odd bit or bob of maturity, it's most often the result of responsibilities foisted on them by wives and offspring. Left to their own devices, men would continue being boys indefinitely. I hadn't quite appreciated the emotional retardation until I started to write a novel about a group of men in their thirties who are more or less single. It dawned on me that every such group of men I had ever come across were hopeless and hapless - effectively, boys with grey hair, or no hair at all.

I feel I can speak with authority on the subject of men behaving badly, and madly, and sadly. Plus I can draw on my experience, having exchanged, only in my forties and only in this millennium, the life of the sparkling young bachelor about town for a new role as wise, kindly, toddler dandling father.

My life used to be about pubbing and clubbing. Now it consists of buggies and Huggies. I used to know the best places to get a drink after 11 pm. Now I know where Spot's hiding.

This new-found maturity has been gained not only by settling down but also by the prolonged absence of my male friends. My social life has dwindled into non-existence, what with the difficulty of finding baby-sitters who are sane, competent and over 12 years old, and of my new regime whereby I'm usually tucked up in bed before the end of the Six O'Clock News.

But on the very rare occasion when I have managed to escape - I'm sorry, I meant to type "go out" - for the evening with my erstwhile mates, I've discovered that I have immediately lapsed into old, childish ways. Within mere seconds of walking into a pub I have found that all the hard-fought progress towards grown-upness has counted for nought.

Before I know it, I've started belching, shouting out naughty words, and eating and drinking in a way that guarantees a tummy ache.

And even if I wanted to behave sensibly, there are other men involved, exerting irresistible peer pressure. So that saying a sentence like "No thanks," or "Orange juice, please" is acceptable only if the man saying it is on a 12-step programme or medication. And of course it's just as impossible to have anything like a normal conversation as it is to ask the kind of adult questions which start with "how". ("How's the wife?", "How are the kids?" - none of them are possible, I'm afraid.)

The regression inherent in male bonding is particularly bad if the pals and you go way back, since old pals can be relied on to retell any incident that ended in your abject humiliation, no matter how long ago. That time at primary school when you called the teacher "mummy" or when you peed yourself in gym.

A symptom of the youthful high spirits of allegedly adult males is the continuing use of schoolday nicknames. Fortunately for me, the nicknames I have kept for the past 30 years haven't been too appalling - although there's no way I'm repeating any of them here. Even more fortunately, there was another chap called Ritchie at my school who was saddled with the traditional Scottish nickname for chaps called Ritchie, and he's still called "Mabawza" to this day. (If you don't get it, try saying it quickly and in a Scottish accent.)

So, too, is a man who was once in my class and whose passport name is John Balfour - his parents had chosen the blandest name for him in the fond hope that this would prevent him getting any abuse. What Mr and Mrs Balfour hadn't reckoned on was that, at the canteen on their son's first day at big school, the pressure got to him. Temporarily forgetting the existence of the noun "custard", and for no apparent reason, he told the dinner lady that what he wanted on his treacle tart was "sauce". With disastrous and permanent results, as I discovered on my last trip back home and bumped into a now 44-year-old Sauce Balfour.

Short of a chromosome transplant, there is still a way for Sauce, me, Gary and Tony to avoid the regressions and humiliations inherent in male-male friendship. We could spurn all our men friends. We could stay in for the rest of our lives, reading about Spot, or venture out only in the company of women. That way we might grow up. That way we'd never need behave badly ever again.

Harry Ritchie's novel, Friday Night Club is published by Hodder and Stoughton, £14.99.