Kate Galantha, 28, took a full seven years to complete her college degree, attending three different institutions. She finally graduated with an "undeclared" major in 2001 and began work as a nanny. She has moved six times since 1999 and is apparently unsure of her next move.

Zach Braff, 29, a film director and actor, explains his perception of the generational trend. "In the past, people got married and got a job and had kids, but now there's a new 10 years that people are using to try and find out what kind of life they want to lead. For a lot of people, the weight of all the possibility is overwhelming."

Grossman argues that this pattern of delayed adulthood is a permanent cultural shift. "In the past, people moved from childhood to adolescence and from adolescence to adulthood, but today there is a new, intermediate phase along the way. The years from 18 until 25 and even beyond have become a distinct and separate life stage, a strange transitional never-never land between adolescence and adulthood in which people stall for a few extra years, putting off the iron cage of adult responsibility that constantly threatens to crash down on them. They're betwixt and between."

Social scientists debate the significance of this new phenomenon. Some see this trend towards delayed adulthood as a good thing. Advocates for the trend suggest that these young Americans are simply enjoying the benefits won by advocates of social liberation. Furthermore, they have grown up in a culture of affluence that has afforded them unprecedented options, creature comforts, and security. They simply do not want to enter the more insecure world of adult responsibility.

Jeffrey Arnett, who sees what he calls "emerging adulthood" as a positive trend, teaches developmental psychology at the University of Maryland. These unsettled young Americans are simply taking their time to focus on adult responsibility. "This is the one time of their lives when they're not responsible for anyone else or to anyone else," he argues. "So they have this wonderful freedom to really focus on their own lives and work on becoming the kind of person they want to be."

In other words, Arnett sees delayed adulthood as a new social phenomenon that allows self-centered Americans even more time to focus on themselves while "not responsible for anyone else or to anyone else." Of course, what Arnett celebrates, others see as the very heart of the problem.

After all, what are these young people doing during this stage of "emerging adulthood?" Well, they're having a lot of sex, for one thing. Obviously, social trends point to demographic generalities, not to every individual in this age cohort. Still, even TIME registered surprise at the sexual attitudes of these unmarried twenty and thirty-somethings.

The delay of marriage is the most significant statistical marker. The average age of first marriage for a white American male is now almost 28--a full six years later than just a few decades ago. This trend is not uniquely American. The average age for a man's first marriage in Canada is 28, in England 29.7. Germany and Italy come in with even higher ages, 30.3 and 30.5 respectively.