Today's twentysomethings have the luxury of delaying life's big decisions. Is that so bad, asks 'emerging adult' Fiona McCann

The Christmas lights are switched on and the coming weeks are already chock-full of engagements: parties, hairdressing appointments, dinners, depilations and the like. A busy period, indeed, as this time of year has been for generations. Except that when my mother was my age, her calendar entries focused on food preparation rather than cocktail consumption, reflecting her annual task of putting together a Christmas feast for a husband, three small girls and the occasional unmarried uncle.

The three small girls are well grown up, but for my mother, now in her 60s, very little has changed. She still spends much of December baking puddings, planning menus and sourcing turkeys while I'm left free to trip around town like a feckless adolescent, safe in the knowledge that someone else will look after the main event.

This year, however, my older sister is hosting the Christmas dinner for the first time, and I'm concerned that her unprecedented gesture suggests a time may come when I too am expected to take my turn. The thought, quite frankly, is terrifying. All that time shopping for food, weighing the turkey, mincing the pies - frankly, my entire December would be a write-off. But it does beg the question: when are adults like me - having been officially counted as such since I turned 18 some 15 years ago - required to step up to the turkey baster? Thankfully, US psychologist Jeffrey Arnett has provided me with some respite by coining a new term for the time of life when you're no longer an adolescent but not yet a fully paid-up adult: "emerging adulthood".

"What happens in their 20s for most people doesn't fit very well into what we have traditionally thought of as either adolescence or adulthood," says Arnett, in Dublin recently to deliver a lecture on this subject at Trinity College Dublin's Children's Research Centre. "All these things are going on that didn't go on 30, 40 or 50 years ago for most people, and they make the 20s unique. So that's why I felt there was a need for a term that distinguished this as a new period."

It's a cheering thought that, given the lengthening life expectancy of those of us fortunate enough to live in developed countries, we've now been gifted an entire decade to delay such monumental life decisions as who to share it with and where to live. And while there is much tut-tutting from those who decry such procrastination as the self-indulgence of grown-ups unwilling to grow up, Arnett is ready with his defence.

"I don't see them [emerging adults] as selfish. I do see them as self-focused, but I think there's a difference," says Arnett. "It's not that they're concerned about no one but themselves, it's that they realise they have a brief window of time in their 20s when they're going to be able to do things that they're not able to do before or after, so they wisely make the most of their freedom."

SUDDENLY THEY APPEAR to be wise as opposed to simply commitment-phobic.

"Emerging adulthood is a time of exploration with the ultimate goal of making choices that are going to be good ones in love and work," Arnett says. "They [emerging adults] are not just indulging themselves without a care for the future. I think they're aware of how they're setting the foundation for what their adult lives are going to be like."

Twenty-three-year-old Nancy, who is setting off for Australia next spring, corroborates the theory that not only has this attitude become acceptable, but almost obligatory for those in their 20s.

"You feel like you have to take off or you'll turn around at 30 and feel you haven't gone anywhere," she says. But all this gadding about is done very much with an eye on the future. "I'd like to get it done young so that when I come back, once I've got it all out of my system, then I can go full steam ahead into my career."

The fact that Nancy rents her own apartment means she doesn't qualify as a "Kipper" (Kids In Parents' Pockets Eroding Retirement Savings), the nickname bestowed on those who live with and off their parents well into their 20s and sometimes 30s. But these are the people giving emerging adulthood a bad name, and Arnett is at pains to point out that they are the exception rather than the rule.

"It's very rare that someone just takes advantage of how easy it is to remain at home," he says.

Even Arnett admits, however, that emerging adulthood can still take its toll on parents who find themselves rowing in with financial and other kinds of support when the unstable lifestyle of the twentysomething takes its toll.

"It's true that parents now provide more support to their kids for longer than ever before," says Arnett. "If you don't get married until your early 30s, then throughout your 20s there may be various times when you need help and you don't have a partner or spouse to rely on. Where else are you going to go if you lose your job or you've been cohabiting with a partner and you break up?"

Most will end up turning to home, it appears, with parents footing the emotional or financial bill, even if it's for a finite period of time.

Arnett claims that most parents are happy to help their offspring if they think there is a plan or at least an intention to get things back on track. His point, however, is that this new period of time does not mean youngsters don't become responsible adults - it's just that they do so later. In Ireland, the average age for a man to marry is now 33 (31 for a woman), but while the bride and groom may be considerably older than their counterparts a generation ago, the amount of people getting married has only marginally declined.

It would appear then that most do settle down in the end, but emerging adults are clearly not in any rush.

"I do want to get married and have kids eventually, but I can't envisage that day happening for a long, long time," admits Nancy, who broke from a long-term boyfriend recently because her partner was looking for more commitment. "I was in a relationship for three years with someone I loved with all my heart, and there was never a day that I was with him that was bad, until he alluded to the fact that he wanted to get married."

At 23, Nancy felt she wasn't ready, but says she has a "grand master plan" to get married in her 30s.

THAT'S ALL VERY well and good, but isn't there a danger that such a rate of psychological development may end up out of sync with an unchanging biological imperative?

"It's not as big a problem as is sometimes portrayed," claims Arnett. "A woman of, say, 32 or 33 who's trying to have a child is very likely to be able to conceive; less likely than if she was trying when she was 20, but still very likely."

Perhaps the bigger danger is that those of us - I mean them - who spend the first 10 years of their adult life having a grand old time changing jobs and countries may find it hard to give that up. The restlessness of emerging adulthood could feed into a lifestyle that becomes impossible to relinquish.

Arnett doesn't see it that way. "People reach a point where they've had enough of the instability or the exploration of emerging adulthood, and they begin to want something that's more enduring, and for most people that's by around age 30," he says. "So there are very few people who want to just keep going perpetually changing love partners every six months or so and changing jobs every year or two. It just gets tiresome."

Around age 30? I'm already three years late, without marriage or children, although I can now tick the mortgage and job box with an exuberant flourish.

But it appears that, at 33, my development is still as arrested as it was when emerging adulthood didn't exist. It could be that my life will always be a series of short-lived joys rather than one long contentment. However, to parental pressures, biological clocks, societal demands and the pension scheme leaflets the bank now include with my credit-card bills, I must add this new knowledge that even my delayed development is delayed.

It may, according to family, society and eminent psychologists, be time to catch up, but not if it involves cooking Christmas dinner. On that, at least, I'm pretty sure my family would concur.