Marc Carlson, who has six weeks of paid parental leave, pushes his daughter, Rebecca, outside their Michigan home as his wife, Diana Carlson, heads to work. (James Fassinger/For The Washington Post)

Marc Carlson, a senior manager at Ernst & Young in Detroit, took two weeks of the company’s standard paid parental leave for dads when his daughter, Rebecca, was born last year. Then, when his wife, Diana, went back to work as a physician, Carlson declared himself the primary caregiver and took the maximum four additional weeks of paid leave.

Carlson, 35, changed diapers, took Rebecca for walks and struggled for what seemed like hours to get the uncooperative baby to drink from a bottle.

“From the beginning, my wife and I really wanted our child care to be shared. And I wanted to be engaged with my kid,” Carlson said. “I was a little hesitant about taking the full six weeks off. But I wasn’t worried about the stigma, or whether it would affect my career advancement. I was more worried about the mountain of work I’d return to.”

Carlson is part of a generation of young fathers who tell pollsters they want to be more than a paycheck, or the fun dad on weekends, and instead to be fully involved in parenthood. In a recently released Boston College survey of 1,000 fathers, the majority rated paid parental leave as important or extremely important, although 96 percent reported they could take two weeks or less. Some said their companies gave them one day.

But a number of companies, taking heed of fathers like Carlson, are expanding paternal paid leave. More than 500 dads a year now take at least the two-week paid leave offered by Ernst & Young, said Karyn Twaronite, partner and inclusiveness officer. State Street, a Boston-based financial services company, has doubled paid leave for fathers to four weeks. And high-tech companies like Yahoo and Facebook — in the vanguard of the movement promoting fathers as caregivers — offer fathers eight and 12 weeks, respectively, of paid leave.

“Traditionally, it was always the mother who took time off to care for new family members. But we’re seeing a real shift,” said Lisa Horn of the Society for Human Resource Management, a business membership group that tracks benefit trends. “Companies that offer paid parental leave for fathers are setting themselves up for a real competitive advantage.”

The Equal Employment Opportunity Commission (EEOC) issued guidelines last week that call for employers to give equal parental leave time to mothers and fathers to bond with or care for a new baby. Mothers may still be given additional childbirth, or “pregnancy-related medical,” leave to recuperate.

“It’s clear we need to have changes in our social norms, so that it’s presumed men will want time off to bond with their newborn,” EEOC Commissioner Chai Feldblum said.

Those norms are not changing only in the United States. The International Labor Organization said in a recent report that fathers wanting policies such as paid leave and flexible schedules to take on greater caregiving roles is “likely to be one of the most significant social developments of the 21st century.”

Robert E. Moritz, chairman and senior partner of PriceWaterhouseCoopers, said the professional service network’s surveys have found that 70 percent of millennial employees see flexible work environments as “hugely important,” as do 60 percent of baby boomers. “The difference is, the millennials are willing to walk,” he said at a recent White House Summit on Working Families. “They want choices.”

(The company offers primary-care parents, including adoptive parents, 12 to 14 weeks of paid time off, and three weeks’ leave for non-primary-care parents.)

Aaron Gouveia, 34, is a case in point. Gouveia was working as a newspaper reporter when his first child was born six years ago, and with no paid parental leave, he cobbled together vacation and sick time to be at home with his infant.

He quit and went to work for IBM. When his second child was born, he took the company’s two weeks of paid leave.

“The company culture is even more important to me than the company itself,” said Gouveia, who writes the Daddy Files blog. “And I like to work for a company culture that gets it, to work for bosses who understand that we’re all human, and want to spend time with our families.”

Jim Lin, 41, who works in public relations in San Francisco and writes the Busy Dad blog, quit his old job on the spot a few years ago when his boss gave him grief for taking two sick days to care for his son. “My boss implied that that was my wife’s job,” he said. “And I just didn’t want to be in that kind of work environment.”

Views like Lin’s — he calls them “Father First” attitudes — which once might have been outliers are gaining traction as they spread through social media and virtual connections. When Lin began blogging in 2007, there were perhaps 15 other dad bloggers, he said. Now, he belongs to a private Facebook group of more than 800. “This generation of fathers is so much more vocal about involved parenting, and the Internet spreads those ideals,” he said.

These blogging dads came out loudly in support of Dan Murphy, the New York Mets second baseman, after some talk radio jocks ripped into him for missing Opening Day while his wife gave birth to their first child. The radio hosts later apologized. Murphy took his full two days of parental leave.

How we’re built

That more men want to take on care-giving roles comes as no surprise to scientists.

Paul Raeburn, author of “Do Fathers Matter? What Science Is Telling Us About the Parent We’ve Overlooked” said the stereotypes about men are so strong that until recently, science all but ignored the role of fathers as parents.

“If you asked a psychologist in the 1970s what fathers do for their kids, especially young kids, the answer would have been, ‘Not much,’ ” Raeburn said. “The most important thing people thought fathers did was earn money and keep their kids out of poverty — which is a good thing — but that was the beginning and the end of it.”

Emerging science is finding that men bond with their children even before birth as their testosterone levels drop and their levels of oxytocin, the bonding hormone, and prolactin, the hormone that produces breast milk in women, rise. Fathers who are warm and engaged also strengthen a child’s healthy development, Raeburn said. And studies have found that it is fathers who stretch their young children’s vocabularies and help with language acquisition.

“Mothers tend to tune their language more closely to the child,” he said. “But fathers use a broader vocabulary. They use words the child doesn’t know. And that pulls the child forward, helps them more rapidly develop language ability and eases their transition into school.”

Science is also showing that becoming a good parent is less about a mythological maternal instinct, he said, and more about having the time early on to develop the competence and the skill. “I didn’t hit the issue of paid parental leave hard in my book,” Raeburn said, “but I provided all the ammunition for why it’s important.”

Uphill battle

Still, fathers who want to do more caregiving from the start face a steep uphill battle.

Only 14 percent of U.S. companies offer paid parental leave to mothers or fathers, down from 16 percent in 2008, and many offer only partial salary replacement, according to the Families and Work Institute. Unlike any other advanced economy in the world, the United States offers only unpaid leave under the Family and Medical Leave Act, which doesn’t cover 40 percent of the workforce.

And one in five companies that are required by law to offer unpaid leave to fathers don’t, the study found. “This is clearly one place where business policy has not caught up with changing demographics,” institute president Ellen Galinsky said.

In June, President Obama called for paid parental leave, saying, “A whole lot of fathers would love to be home for their new baby’s first weeks in the world.” Obama didn’t endorse paid-leave legislation pending in Congress. Instead, he offered funds for five states to explore how to craft paid-leave programs. Three states — California, New Jersey and Rhode Island — now have employee-paid parental leave programs.

Some lawmakers and business groups who oppose paid parental leave say such a program will be too expensive, create too much bureaucracy, increase costs to business and could lead to a drop in wages. The U.S. Chamber of Commerce and other business groups have lobbied against paid-leave proposals. Others oppose extending leave to fathers as “not natural,” with one writer in Britain vowing, “If God had meant men to have paternity leave, he would have given us all wombs.”

That traditional view, argues Josh Levs, a journalist for CNN, is a big reason why companies give fathers shorter leaves than mothers, and why many fathers don’t take any leave at all.

“As men in this country, we are literally leaving hundreds of millions of dollars on the table in unused parental leave, and the biggest reason is: They’re afraid to take it,” Levs said. “Study after study shows that when men come back from taking parental leave, they’re often treated worse by their colleagues and their bosses. Their reputations are damaged. They’re demoted or given less work, because we have these stigmas that dads are supposed to work and moms are supposed to stay home.”

Last fall, Levs filed one of the first complaints with the EEOC alleging discrimination against fathers after his employer, Time Warner, refused to grant him equal paid-leave time. Time Warner offers biological mothers and adoptive mothers and fathers 10 weeks of paid parental leave, but allows biological fathers only two, even when they plan, like Levs did, to be the primary caregiver.

Other discrimination cases include a father in Ohio who alleges he was passed over for promotion because he took unpaid leave to care for his children and was shunned and defamed, and a father who said he was terminated after he asked to extend his five-day parental leave and was refused.

“There’s still a powerful stereotype that real men work; real men earn wages,” said Brad Harrington, director of Boston College’s Center for Work and Family. “Women who take extended leave might be seen as less-committed workers, but they’re seen as better women, because the stereotype is that’s the ‘right’ thing for women to do. But the irony for men is, they’re perceived not only as lesser workers if they take leave, but lesser men.”

For gay fathers, the dearth of paid leave for men can sometimes mean that neither father can take much time to bond with their children. Kipp Jarecke-Cheng saved up five weeks of vacation and sick time and paid about $1,200 to be off another four weeks when he and his partner adopted their son from Vietnam.

“The place where I worked when we adopted our son did have a paid leave policy for mothers, but not for fathers,” he said. “It was very much tied to the notion that women need bonding time with infants, but dads don’t. But even if I had a female partner who had given birth, I’d want to spend that time with my child.”

Other companies, like Scholastic, treat gay fathers as they would any primary caregiver. “I was very lucky. I was given the full leave package that women get, minus the medical leave,” said Michael Strouse, director of retail operations at Scholastic’s store in New York. “I got eight weeks of paid bonding leave and another eight weeks working part time on transitional leave. All at full pay.”

Strouse’s husband had no paid leave. So Strouse, like women with long leaves, became the primary caregiver. “It’s a function of experience more than anything else. And my husband just didn’t have the opportunity.”

leave for men, equity for women

Janet Gornick, a professor of political science and sociology at the City University of New York’s Graduate Center who studies paid-leave policies around the globe, said that traditional attitudes about gender still hold powerful sway even in countries with generous paid parental leave policies. In France, Germany and Austria, for example, 2 percent of fathers take paid leave, compared to 90 percent of mothers.

“European countries realized that instead of promoting gender equality, these leave policies were retarding it,” Gornick said. So several countries developed “use it or lose it” programs. If fathers don’t use their allotted leave time, the family loses it. “That changed father behavior overnight.”

In 2000, a movement of young fathers led Iceland to change its paid leave to a “use it or lose it” system. Now, mothers and fathers each have three months’ paid leave and three months the family can share. And lawmakers have promised to extend the leaves for both parents to five months, with two months to share, and increase the pay in coming years, despite the fiscal crisis of 2008 that bankrupted the country.

Today, 90 percent of all fathers in Iceland take paid parental leave.

As a result of the “father quota,” a recent report found, 70 percent of parents who live together continue to share child-care duties three years later, up from 40 percent.

In the United States, where mothers have longer parental leaves, time studies show that mothers still do about twice the housework and child care, on average, even when they work full time.

“This is one of the biggest factors in preventing women from leaning in to the workplace,” CNN’s Levs said. “Our current policies police men out of caregiving roles and police women into them. And we have to stop. Giving adequate, substantial parental leave for fathers is good — good for fathers, good for gender equality and good for business.”

Anthony Mitchell, 46, of Atlanta, told his employer that he planned to take only a few vacation days when his wife gave birth to their first child. He assumed that’s all he’d get. His employer, Catalyst, a nonprofit group dedicated to women’s advancement and gender equality, set him straight.

“They said, ‘What are you talking about? You get parental leave!’ almost like it was a foregone conclusion,” Mitchell said. He took six weeks of paid leave and worked reduced, flexible hours for another two. “There was so much fear of the unknown for both my wife and I. For us to be able to handle those things together as true partners was huge.”

Although Mitchell was initially worried about missing so much work, his colleagues and clients were supportive, saying, “This is a time in life that you never get back.”