Grow older? Not much trick to that. Grow up? Now there's the challenge. Look at Ben Roethlisberger.

It's not unusual for a judge to lecture a defendant at sentencing. But when a Georgia district attorney announces no criminal charges will be filed in a case involving a female college student in a bar, then proceeds to deliver the 28-year-old an admonishment to "grow up," something is clearly amiss.

In a culture that makes heroes of the dopey young folk from MTV's "Jersey Shore" and a dopey slacker in CBS's "Two and a Half Men," what does the call to adulthood even mean?

Gary Cross is a professor of history at Penn State University whose most recent book, "Men to Boys: The Making of Modern Immaturity," addresses just that.

"This trend has been building up over the last 50 years to where today it really is hard to see [role] models, to recognize these models of maturity," he said. "Men have, in effect, slowly and not always steadily rebelled against the role of being providers and being sacrificers."

The old familiar rites of passage included graduation from college, securing employment, marriage, starting a family -- but not necessarily participating in the child-rearing -- and in many cases, conscription into the U.S. armed forces.

Now, "Men who are in their mid-20s are more independent for a longer period than before because of the rise in the age of marriage. In 1970, when I was 24, men married at 22. Now they're married at 28; that's a big difference," Dr. Cross said.

Women are getting married at a later age as well (25.6 years) but for some reason, the idea that they, too, must "grow up" is not really at issue. For starters, women have made great strides in terms of education and employment -- although they're still not as well-paid as male counterparts -- over the past 50 years.

Women also have often been the ones to cook, clean and care for younger siblings in their "family of origin," so experts note it's not that big a stretch for them to transition into these work roles with a new "family of orientation."

"Part of it is the way boys have always been indulged more than girls in the typical family," Dr. Cross said.

"One thing that has struck me is, early in the 20th century, how indulgent they were of openly naughty boys. Not so much with the girls."

This "boys-will-be-boys" attitude doesn't bode well for the future of a society more interested in photos of Tigers Woods' bevy of mistresses than health care reform. We know everything about Jesse James and Jon Gosselin, so it's no surprise that Big Ben dominates the chat forums this week.

We as a nation embrace our immaturity, and no wonder. A recent Del Webb Boomer Survey of 1,000 participants ages 50 to 65 report they feel "10 to 15 years younger than their actual ages."

It's not the age, it's the attitude. And many 20-somethings, on the younger end of Generation X, are acting like high school kids. They have had to work less than previous generations, with fewer role models in the home or in popular culture.

There is, said Dr. Cross "a celebration of this sort of immaturity," from Adam Sandler movies to E! Network's coverage of life at the Playboy Mansion.

It's easy to name the bad boys of pop culture, but finding an example of a positive male provider on television is not easy, beyond a handful of shows such as "Modern Family" or "Castle."

Michael Kimmel, a professor of sociology at the State University of New York at Stony Brook, has written extensively about men and masculinity. His latest book, "Guyland: The Perilous World Where Boys Become Men," concludes that in America, white men ages 16 to 26 are often confused about their roles in society.

"About 40 percent of all college students, male and female, will move back home after college, and not just for the summer," he said. "Part of that is economy-driven and I don't think this is necessarily a concern.

"But I think there is a larger question, and not simply that guys are failing to grow up, that there is that 'failure to launch.'

"There is this new strategy of development, this continuation of the college party life."

But when it comes to immature behavior, naughty is one thing, unprofessional is another. In the case of Roethlisberger, his free time really isn't his own, even if he works wonders on Sundays.

"There is really a sharp difference between responsibility and maturity at work, and off work," Dr. Cross said. "I'm sure Roethlisberger doesn't goof off and act like a jerk on the football field."

Hanging out in bars with college kids, he added, should be verboten to someone of his stature: "He has responsibilities that extend beyond his personal desires or feelings at the moment. He is a public figure, presumably admired by children."

"He is supposed to be a role model -- there are kids out there wearing his number," Dr. Kimmel said. "It's like taking a quote out of 'Spider-Man:' 'With great power comes great responsibility.' "

Doug Oster writes a blog, "Growing With Doug," exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.