Boomerang Kids

Sanchez doesn't pay any rent, although his father, a pharmacist, persuaded him to buy a house lot and to start saving. He also owns a truck and a Harley-Davidson motorcycle.

"He lives here and sleeps here and eats here when it's convenient," said his mother, Velva. "He comes and goes as he pleases."

For Andrew Schrage, a 2008 Brown University graduate, returning to his parents' Boston home was a matter of choice, not necessity. The 26-year-old co-owner of Moneycrashers.com, a Denver-based personal-finance website, was an adolescent when the bursting dot-com bubble ended an 18-year bull market marked by an almost 15-fold gain in the Standard & Poor's 500 Index.

"I enjoy spending time with my parents and want to do so as much as possible, especially while they are younger," Schrage said by e-mail. He helps them with household bills and chores.

The Downside

"I don't have as much privacy as I'd like," Schrage said on the downside of his living arrangements. "My parents like to make comments about lots of 'little things,' which can really get on my nerves."

About a third of adults 18 to 34 who live with a parent said the move has been good for the relationship, according to a March report by the Pew Research Center's Social and Demographic Trends Project in Washington. Only 18 percent said the move had caused relationships with their parents to deteriorate.

More than 60 percent of adults 25 to 34 know friends or family members who have moved back with their parents in the past few years because of economic conditions, according to the Pew report. It cited a December telephone poll of 2,048 adults, with a margin of error of plus or minus 2.9 percentage points.

The share of Americans living in multigenerational households reached the highest level since the 1950s, after rising significantly over the past five years, according to Pew.

Comfortable Lifestyle

"Young adults have had record-high unemployment rates," said Kim Parker, the Pew study's author. "So many of them have either moved back home, or have never left."