NEW YORK (CNNMoney) -- Stay-at-home dads are no longer such a rarity on the playground.
The number of stay-at-home dads has nearly doubled since 1989, according to a new Pew Research Center report released Thursday.
Numbering 2 million in 2012, men now represent 16% of stay-at-home parents -- up from 10% in 1989.
Driving this growth is a surge in the number of men who are staying home purely because they want to care for their children. The number of dads in this camp has quadrupled from 5% in 1989 to 21% in 2012.
But not all dads stay home by choice. In fact, the majority have fallen into this role because they can't find a job or are dealing with a health issue.
In 2012, 23% of dads said they stay at home because they are unable to find work -- up from 15% in 1989. And the biggest share, or 35%, say they are in this situation because they are ill or disabled -- a percentage that is down significantly from 56% in 1989.
Stay-at-home dads are twice as likely to lack a high school diploma as a working dad, and nearly half of at-home dads live in poverty (often because they don't have a working spouse) -- versus only 8% of working fathers.
The situation is similar for stay-at-home moms. One of the traits that separates the two is age: Only 24% of at-home fathers are under the age of 35, compared to 42% of stay-at-home moms. And dads are twice as likely to be 45 or older.
The number of stay-at-home moms has also been on the rise as many women struggle to find jobs that pay enough to cover the cost of childcare, according to a separate Pew report released earlier this year.
There are different definitions of a stay-at-home parent. Pew's report includes both married and unmarried fathers with children under the age of 18, and does not take into account whether or not their spouse or partner worked during the previous year. The Census Bureau takes a more limited approach, estimating that there are only 214,000 stay-at-home dads in the country.
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