The economic downturn has postponed growing up, as millions of adult children are unemployed and stuck at home with Mom and Dad.

The number of jobless adult children living at home with their parents has doubled since 2007, from 1.3 million then to 2.5 million this year, according to Moody's Analytics data cited by The New York Times.

But as the economy improves, some of them are starting to land new jobs. Many adult children finally are moving out, according to Census Bureau data. The rate of household formation in the U.S. has doubled from its average level during the downturn, and now is hovering close to pre-recession levels.

And that's good news given that economists view household formation as a key bellwether for the economy, since it is closely linked to the housing market and consumer spending. They say that once young people start to form new households in earnest, then the housing market may truly rebound. The housing market has been picking up in recent months, and economists view a housing recovery as an essential part of a broader economic recovery.

Still, young Americans have been hit disproportionately hard by the economic downturn, largely because they have less job experience. The unemployment rate for 20- to 24-year-olds was 13.2 percent in October, according to the Labor Department: double the unemployment rate for workers aged 25 and older.

Even those young people that have jobs are often underemployed, with many stuck in part-time work or working in a low-paying jobs that does not use their skills.

Earlier on HuffPost:

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