When Linda Perlman Gordon's daughter, Emily, moved back into their Chevy Chase home for more than a year after college, it wasn't an embarrassment or a defeat or a sign of too-taut apron strings. It was "fiscally responsible, as opposed to just bankrolling her," says Gordon, a clinical social worker.

Emily, who eventually went on to medical school and is now a 31-year-old doctor in San Francisco, was going through a new stage of life that Gordon calls "adultescence" -- the seemingly endless stretch of time between prom night and confident adult self-sufficiency (some of us, to be sure, never get there). Gordon coined the term with Susan Morris Shaffer, an expert on gender-related issues and education, for "Mom, Can I Move Back In With You?" It's a "survival guide" they wrote and published this year to advise and support parents of today's slow-to-mature twenty-somethings.

"Unfortunately," they write, "there is no separate category for 20 to 30, such as the 'terrible twos,' to reassure parents."

Gordon and Shaffer want to dispel the shame that, at least among large segments of the middle class, is associated with having a twenty-something at home (or being one, for that matter). They believe that adultescence is the "new normal" that needs to be destigmatized considering that twenty-somethings are far more likely than their predecessors to end up bouncing back to Mom and Dad for a few months or years.

Gordon explains, "Parents of twenty-somethings are just kind of suffering alone. It's really kind of hard for them."

Shaffer says that parental hardships include the burden of being the so-called sandwich generation.

"This is a time when we're preparing for retirement, and all of a sudden you find yourself taking care of your parents and your kids. And if you see your kids not pulling their own weight, that's a source of tremendous conflict.

"The two things parents want to see in their kids in their twenties is a sense of purpose and an independent identity."

As long as your adult children show signs of both of these things, the authors insist, having them at home can be an okay, or even rewarding, experience.

It's not a new phenomenon -- "boomerang" kids, as the media often call the home-again set, were dubbed "adultolescents" by Newsweek in 2002 ("the Me Generation Is Raising the Mini-Me Generation" was the article's subhead). Young people are marrying later in their twenties and the job market continues to stagnate while housing prices, at least in the Washington area, soar. A 2002 poll reported that 62 percent of graduating college seniors planned to move home for a period of time, and the 2000 Census reports 10.5 percent of Americans 25 to 34 living in their parents' houses, compared with 8 percent in 1970, the low point for adults moving home. (You couldn't trust anyone over 30, remember?)

Many twenty-somethings now view moving home as a reasonable alternative to paying high rents on an entry-level salary while wrestling with student loans and quarter-life crises.

Emily Gordon calls it "an obvious decision. I knew that I was going to go back to school. I just wanted to get my bearings." (In other countries, of course, it's customary for adult children to live at home -- plenty never leave at all. Italian parents don't face an empty nest until their children are, on average, 34.)

Jeffrey Jensen Arnett, a psychology professor at the University of Maryland who's just published "Emerging Adulthood: The Winding Road From the Late Teens Through the Twenties," notes that these days about 40 percent of children move back home for some period of time, something that reflects changing times, not necessarily poor parenting.

"It takes longer to get to adulthood than it did 40 years ago," he says, "but maybe that's a good thing. Maybe they'll have a better shot at happiness than all the people who got married at 20 and divorced."

Shaffer admits, though, that the intense involvement baby boomers have had in their children's lives -- some might call it coddling -- has had a downside, which is: "kids with a sense of entitlement, a lack of long-range goals, a lack of persistence. . . . And they tend to see us as their personal concierges."

She interviewed one unhappy father who told her that his adult son "doesn't understand why he has to work."

The authors characterize this new generation, somewhat sympathetically, as financially insecure, indecisive and disillusioned, but they also agree with Arnett: Rather than being viewed as a form of failure, depending on the circumstances, moving back home can say something positive about the modern family dynamic. These kids have a more natural bond with their young-minded, pop-culture-savvy parents.

Shaffer, whose 21- and 29-year-old children are living independently (for now, anyway), says of her own generation, "I think we would have rather slit our throats than move back home. There's a comfort level that our kids have with us that we didn't necessarily have with our parents. We listen to a lot of the same music. We have a dialogue about movies."

Susan Zohlman, a 57-year-old interior designer in Chevy Chase whose two sons, now 28 and 31, both moved home for a year or more after college, says it's a different world than the one she grew up in. She remembers talking to her parents every three months during her college years, and left home to be married two months after graduation.

"It's generational," she says.

Now she sees many benefits to long-term "respectful interdependence" -- as Gordon and Shaffer put it -- with her adult kids. One son, a medical resident in Manhattan, lives in a co-op owned by his parents, and the other is a chef living in the family's second home in California. Both pay some rent, and it's become a smooth give-and-take (if a bit one-sided). During her sons' first post-college return to the fold, Zohlman admits, there were some minor tensions. While curfews are out of the question at that age, "I did like to be called, you know, 'I'm going to be late.' It's the same courtesy you'd give anyone you're living with."

She adds, "You really no longer have control, so you can try to have communication instead of control."

Sometimes the arrangement helps the parents just as much, or even more, than it helps the kids. In Sandy Seestedt's case, keeping the nest full is a financial necessity right now. Seestedt, 48, is a beginning real estate agent recovering from a divorce, and has welcomed her 26- and 22-year-old sons back into her Adams Morgan home. They pay rent, do their own laundry and help their 13-year-old sister, Jane, with her homework.

"I love living with them," Seestedt says. "They're really great people." As far as when they'll all pack up and leave, she says, "They're waiting for me to get on my feet. They're very much helping me."

It's not always a big hugfest, of course. Arnett notes that while "emerging adults" generally like their parents more than they did as adolescents, "they do get along better when they're not living together."

And Gordon reminds parents not to "assume they are adults because they are physically large."

She adds that parents have to maintain a delicate balance between helping and enabling.

"If we do too much for our kids later, we send them the message that we think they can't do it themselves."

When Emily Gordon returned home, her mother had to restrain herself from imposing her own views on her daughter. "She came home as an adult," she says. "I had to learn how to listen, and I had to learn that she sees the world through her eyes, and that's okay."

Putting out the welcome-back mat: Sandy Seestedt is surrounded by, clockwise from lower left, Peter Conyer, Kristin Finley, Zoe Jackson, Jane Biel, Andrew Conner and Gustav Seestedt.