Correction: An earlier version of this article incorrectly referred to percentage increases in households in which mothers are the sole or primary breadwinners as increases in total numbers. This version has been corrected.

Julie Guyot-Diangone takes her children outside to play near their home. Guyot-Diangone is a single mom and the sole breadwinner. (Astrid Riecken/FOR THE WASHINGTON POST)

In a trend accelerated by the recent recession and an increase in births to single mothers, nearly four in 10 families with children under the age of 18 are now headed by women who are the sole or primary breadwinners for their families, according to a report released Wednesday by the Pew Research Center.

The report reveals a sweeping change in traditional gender roles and family life over a few short decades: The share of married mothers who outearn their husbands has risen from 4 percent in 1960 to 15 percent in 2011. The share of single mothers who are sole providers for their families has increased from 7 to 25 percent over the same period.

“The decade of the 2000s witnessed the most rapid change in the percentage of married mothers earning more than their husbands of any decade since 1960,” said Philip Cohen, a University of Maryland sociologist who studies gender and family trends. “This reflects the larger job losses experienced by men at the beginning of the Great Recession. Also, some women decided to work more hours or seek better jobs in response to their husbands’ job loss, potential loss or declining wages.”

But the Pew Research report shows that Americans are decidedly ambivalent about mothers who work outside the home. Three-fourths of those surveyed say these mothers make raising children harder, and half worry that it’s bad for marriages.

About half of those surveyed felt it was better if mothers stayed home with young children. In contrast, 8 percent thought it was better if fathers did.

But at the same time, the report notes that other polls have found that nearly 80 percent of Americans don’t think mothers should return to a traditional 1950s middle-class housewife role.

“The public is really of two minds,” said Kim Parker, one of the report’s authors. Traditional gender roles “are a deeply ingrained set of beliefs. It will take a while for those views to catch up with the reality of the way people are living today.”

While not perfect, it’s a lifestyle that suits Lisa Rohrer, who works at Georgetown University Law Center, as well as her family. Rohrer became the primary breadwinner when her husband, JJ, started his own business. He now picks their two kids up from school, stays home when they are sick and does much of the housework.

“For us, it has been ideal in many ways, because it has allowed JJ to pursue his dream of starting his own business and has allowed me to take jobs that require a lot of time and travel. I’m also glad our kids see an alternative way of handling careers, marriage and kids,” she said. “On the other hand, I have a lot more sympathy for dads in families where their wives are staying at home. There is a lot of pressure when you’re the main breadwinner.”

Although the trend toward mothers who pull in the biggest part of the family income has been on the rise as more women have become educated and entered the workforce, the recession has accelerated the trend, said Sarah Jane Glynn, an analyst with the Center for American Progress.

“Part of what’s happening is that more men have been getting laid off and are having difficulty finding work,” she said, noting that the number of married wives who are sole earners has increased since 2007. “And with the way the recovery’s played out, some men who lost their jobs wound up taking others that paid less.”

The Pew Research report found that married mothers are becoming increasingly better educated than their husbands: 61 percent of husbands and wives in dual-earner households have similar education levels, but 23 percent of the mothers are better educated than their spouses, compared with 16 percent of fathers.

Women began graduating from college in greater numbers than men in 1985 and now earn more advanced degrees in many fields.

The stigma of women out-earning men appears to be waning, at least among those with college educations. About 30 percent of those surveyed think it’s better if men earn more, down from 40 percent in 1997. Those with a high school degree or less, however, are twice as likely as college-educated Americans to think men should earn more.

Heidi Parsons, 44, who owns her own recruiting firm in Alexandria, said attitudes such as that can make being a breadwinner a challenge in a relationship.

“My husband is a massage therapist. The disparity in income is hard for him. I don’t care. I signed up for it. I knew that going in, and it’s never bothered me,” she said. “But it’s hard, because it’s hard for him. What I like to look at is how it was nice that he was home for two years when the kids were little. That’s a contribution there that goes unrecognized on the dad’s side.”

Cohen said the trend toward breadwinning mothers can be disconcerting because it upends the status quo.

“Mothers have historically been responsible for the majority of child care and rearing, and single motherhood represents an extension of that role in a way that does not challenge traditional gender norms,” he said.

Single-mother breadwinners are at a severe disadvantage, the report found.

Compared with their married peers, they earn an average of $23,000 and are more likely to be younger, black or Hispanic and have less education than a college degree.

“The makeup of single mothers has changed dramatically,” said Wendy Wang, one of the report’s authors. “In 1960, the vast majority of single mothers were divorced, separated or widowed. Only 4 percent were never married. But now, it’s 44 percent.” Now, 40 percent of all births are to single mothers, she added.

Julie Guyot-Diangone, 42, a divorced, breadwinning mother of two who works on Capitol Hill, earned a PhD in social work and specializes in orphan and refu­gee displacement. But since both her parents died a few months ago, she has no one to help her take care of her children, much less buy the groceries, cook or do laundry.

“I used to think, when looking for employment, I would look at my area of expertise. But those aren’t necessarily 9-to-5 jobs,” she said. “I find that I’m looking for work hours. Flex time. Teleworking. I’m looking for that, as a priority.”

Marcia Greco, 57, who works in Fairfax, had no choice about becoming her family’s breadwinner when her husband was laid off nearly 20 years ago. Her husband took care of their two children and went to school at night. He felt isolated. Sometimes, people thought of them as a curiosity. Despite that, and despite the unease with mother breadwinners that Pew Research report found, the situation worked for them. The two just celebrated their 30th anniversary.

“We showed our kids that anyone can be a nurturer or go out and be a primary breadwinner,” she said. “Your gender doesn’t matter.”