Know any 30-year-olds who seem unable to hold down a job, pay rent for their childhood rooms — which they still inhabit — or commit to a significant other?

According to the experts, these "children" may still be experiencing the pangs of adolescence which apparently lasts much longer that it once did. In fact, many social scientists are spending big bucks and a lot of time to help these "youngsters" through their sensitive years.

The MacArthur Foundation has funded a $3.4 million project, Transitions to Adulthood, to focus on adolescents as old as 34. The Society for Research in Adolescence is examining the "emerging adulthood" years between 18-29. And the book Quarterlife Crisis: The Unique Challenges of Life in Your Twenties, by Alexandra Robbins and Abby Wilner, became the self-help Bible of choice for maturity-challenged Generation X/Y-ers when it was published last year.

The people behind these projects insist that the state of being a 20-something or even a young 30-something is different at this point in American history than ever before.

"There's a lot more emphasis on figuring yourself out, finding your passion, not settling down until you're absolutely sure," said Robbins, the 25-year-old Quarterlife Crisis co-author. "Back in the day you had fewer decisions to make."

Experts also said more resources were needed to help adult adolescents with their growing pains.

"We need institutions in society to get people through this transition," said Idy Gitelson, senior program officer with the MacArthur Foundation.

Robbins agreed. "We're sheltered 65 percent of us go to college, which is more like summer camp if you think about it. College coddles us it produces waves of young adults not prepared for real life."

She added that individuals in this category don't feel they've become adults until their mid- to late 30s.

"We're more like adolescents than adults, in terms of how we're confronting identity issues."

Society for Research in Adolescence psychologist Jeffrey Arnett believes the phenomenon is partly a result of people marrying and having kids later in life.

"They don't have to buy diapers and formula so they can spend their money on CDs, dinners out, trips to the Caribbean," he said. "It is a leisure-oriented group."

Young women now marry on average at 25, young men at 26.8 about four years later than they did in 1970. They live with their parents longer, too. According to the U.S. Census Bureau, more than half of men ages 18-24, and almost half of women that age, lived with mom and dad last year.

But it's more than just a difference in lifestyle. A lack of adult responsibilities affords young people the time to ponder the "who am I" questions they began asking themselves as teenagers.

"I feel like the identity concerns of adolescence don't go away or haven't gone away yet," said Greg Milner, a 32-year-old editor at Spin magazine. "When I was in my 20s, I kind of figured I'd feel a lot more adult by now than I do."

Pop culture has found a new market in overaged teens. The hit 1995 movie Billy Madison features Adam Sandler as an unemployed 27-year-old who spends his days drinking beer, reading dirty magazines and hanging out by the pool, all at his wealthy father's expense. Sandler himself has made millions portraying an overgrown adolescent.

And the most popular show on television, NBC's Friends, features a group of 20- and 30-somethings who spend most of their time hanging out at their favorite coffee shop.

But not everyone buys the "new" adolescence. Edie Moore, director of the Society for Adolescent Medicine, said 18 is still the cutoff.

"Let's face it — 18-year-olds are adults: They vote, they serve in the military," she said.

Web technician Patrick Whalen, 33, felt the same.

"One night, by the time you reach your thirties, you go out to a bar and suddenly realize you're eight years older than everyone else, even if you do some of the same things.

"There is a vast difference between people my age and teenagers — even if we all wear the same pair of jeans," he said.