Here in the U.S., they're an oddity on the playground: dads who choose to stay home to take care of their babies.
While many new American fathers take some time off to help out and bond with a newborn, most head back to work after a week or two. Few companies offer paid paternity leave, and there's no federal standard. Fathers in California can take up to six weeks off, but only a quarter of them actually do.
Some fear for their jobs if they take too much time off. Others may be uncomfortable in a role that's been a frequent Hollywood punch line in movies like "Mr. Mom" and "Three Men and a Baby."
So overworked American moms might be a little jealous of their counterparts in Sweden.
New mothers and fathers in Sweden can split 14 months of parental leave between them, with 80% of their salaries paid by the government. Fathers are actually required to spend two months at home with the baby on their own, or they forfeit the pay and the time off.
It is known as "daddy leave," and 85% of Swedish fathers now take it. More fathers take more time off for a new baby in Sweden than anywhere else in the world.
"Daddy leave" was first introduced in 1995. It has become so common that the majority of Swedish men say their bosses fully expect them to take time off; colleagues and family members would frown on them if they didn't.
A poster boy for "daddy leave" is Martin Mellin, a police sergeant in Stockholm who became famous for his machismo as the winner of the first Swedish "Survivor" show.
Mellin never pictured himself as a "Mr. Mom" when his two older children were born. But before baby Charlie came along a year ago, his wife Camilla Lackberg set him straight.
"When we started talking about having the baby, I was very specific and very clear, and said if we are going to do that, we have to share," said Lackberg, a best-selling crime writer. "Martin said, 'Absolutely, sign me up,' and he really has been there since day one."
He may have been willing, but Mellin didn't really know what he was getting into. "Before I thought, hey, you're at home with the kids, how hard can it be? But now I know," he said. "You never rest. There is always something to do and you always have to be on your feet. You can't leave him for ten seconds because he will climb on the furniture and stairs, open ovens and find knives."
When he takes Charlie to the playground in the middle of the week, there are at least as many fathers as mothers out with their kids.
Mark Klamberg recently joined the ranks of stay-at-home dads in Sweden.
His wife Birgitta Ohlsson went back to work as Sweden's Minister of European Affairs when their baby daughter, Stella, was only three weeks old. Klamberg watches the baby in a room just steps from his wife's desk so she can stop in and nurse during the day.
The arrangement works for both of them.
"I always say I am married to a modern man, not a dinosaur," Ohlsson says.
In the 15 years since "daddy leave" went into effect, the Swedish birth rate has gone up. The promise of paid time off and shared responsibility may have helped encourage couples to have more children. There are also more women in the workplace now, and divorce rates have dropped.
Martin Mellin, for one, wouldn't have it any other way. "You gain so much being home," he says. "If he's hurt he doesn't go 'Mama! Mama!' He says, 'Dada! Dada!' It's a nice feeling, being that needed."