The results will be disappointing for those who expected more gender equity in modern society.
The study found that three months after the birth of their first child, on days when couples were not working, men were most often relaxing while women did housework or child care.
In contrast, when men were taking care of the kids or working around the house, their partners were most often doing the same thing.
One telling statistic: Women spent 46 to 49 minutes relaxing while men did child care or housework on their day off. But men spent about twice that amount of time in leisure - about 101 minutes - while their partners did some kind of work.
"It's frustrating. Household tasks and child care are still not being shared equally, even among couples who we expected would have more egalitarian views of how to share parenting duties," said Claire Kamp Dush, lead author of the study and associate professor of human sciences at The Ohio State University.
Kamp Dush conducted the study, published online in the journal Sex Roles, with Sarah Schoppe-Sullivan, a professor of human sciences at Ohio State, and Jill Yavorsky, who received her Ph.D. at Ohio State and is now an assistant professor of sociology at the University of North Carolina at Charlotte.
The research included 52 couples who participated in the New Parents Project, an Ohio State study of mostly highly educated, white, dual-earner couples from the Columbus area who were having their first child.
"It is a small sample. It is not the definitive answer, and is mostly relevant to similar couples. But we need to look into this further and understand how dual-earner couples are sharing housework and child care," Kamp Dush said.
One reason for the small sample is the difficulty of doing this kind of study, Kamp Dush said. The researchers are not aware of any other study in which both members of a couple completed detailed time diaries of what they were doing on the same days and at the same times.
The researchers asked the couples to complete their own time diaries for a workday and a non-workday during the third trimester of the woman's pregnancy and about three months after the baby's birth.
On workdays after the baby was born, the amount of time women and men spent doing housework and child care was more equal than on non-workdays, although women still did slightly more work, the results showed.
But men made up for it on non-workdays, when the amount of time they spent in leisure activities actually doubled - from 47 to 101 minutes - between when their partner was pregnant and three months after the birth.
"On non-workdays, parents are more evenly splitting housework and childcare. It's very much 'all hands on deck' but when there is more time available on the weekend and parents are not so pressed to get everything done, then we see the emergence of gendered patterns and inequality where women do a lot more housework and childcare while he leisures," Yavorsky said.
On their days off, men were relaxing 46 percent of the time while their partners did child care. In contrast, women were engaged in leisure only 16 percent of the time when their partners were taking care of their child.
Results were similar for housework, where fathers took 35 percent of the time off while their partner did tasks like cleaning. Women took 19 percent of the time off when men did housework.
Kamp Dush said these highly educated couples where both parents have jobs would be the ones you would expect to have worked out equitable arrangements for sharing housework and child care.
"I was expecting to see a lot more minutes where the couple was doing some kind of housework or child care together. I suspect the situation may be even less equitable for women who don't have all the advantages of the couples in our sample," she said.
There are steps both men and women can take to help even out the inequities found in this study, Kamp Dush said.
Men need to get in there and take care of their child and house, particularly on the weekends, she said. In some cases, moms may need to step back and let fathers do housework and child care tasks without hovering to make sure they meet her standards.
"Couples need to be having conversations, ideally before their baby is born, about how they are going to divide household tasks to make sure they are equitable," she said.
"At the time we studied them, these couples were setting up routines that may last several years as the kids grow. Couples need to be having these conversations from the first few months."