Some couples have forged partnerships they consider fully equitable.

"We'll both talk about how we're so lucky to have someone who does more than their share," said Mary Melchoir, a Washington-based fundraiser for the National Organization for Women, who — like her lawyer husband — works full-time while raising 6-year-old triplets.

"He's the one who makes breakfast and folds the laundry," said Melchoir, 47. "I'm the one who fixes things around the house."

Joshua Coleman, a San Francisco-area psychologist and author of "The Lazy Husband: How to Get Men to Do More Parenting and Housework," said equitable sharing of housework can lead to a happier marriage and more frequent sex.

"If a guy does housework, it looks to the woman like he really cares about her — he's not treating her like a servant," said Coleman, who is affiliated with the Council on Contemporary Families. "And if a woman feels stressed out because the house is a mess and the guy's sitting on the couch while she's vacuuming, that's not going to put her in the mood."

The report's co-authors, sociologists Scott Coltrane of the University of California, Riverside and Oriel Sullivan of Ben Gurion University, said they were addressing a perception that women's gains in the workplace were not being matched by gains at home.

"The typical punch line of many news stories has been that even though women are working longer hours on the job and cutting back their own housework, men are not picking up the slack," Coltrane and Sullivan wrote.

They said this perception was based on unrealistic expectations and underestimated the degree of change "going on behind the scenes" since the 1960s. The change, they said, "is too great a break from the past to be dismissed as a slow and grudging evolution."