Which couples not only have the most sex but the best sex lives?

A)   Conventional couples where women do most of the housework and the traditionally “feminine” chores like laundry, cooking and cleaning, and men, if they do chores at all, help out with more “manly” yard work or car repair?

B)   Egalitarian couples who share the routine housework equitably?

C)   Counter-conventional couples where the man does most of the housework?

If you picked A, the conventional couples, it wouldn’t come as a surprise. That’s the conclusion of one recent influential study that was trumpeted far and wideby the media and across the Web and cast a lackluster pall over what some called “sexless but equal” unions.

But you would be wrong.

That study was based on data collected in 1987 and 1992, and may have been true about a generation ago. (Another study, using the same data, found that the more total paid work and housework couples did, the more sex they had, a “work hard, play hard” theory.”)

But it turns out, using more recent data from 2006, couples who split the housework fairly are the happiest between the sheets. They have the most sex, are the most satisfied with their sex lives, and express the highest level of sexual intimacy.

That’s at least according to new work that will be presented at the upcoming American Sociological Association annual meeting.

“The conventional view, based on data that’s a quarter century old, is that sexual arousal for heterosexual couples is dependent traditional gender roles, on a man being manly and a woman being feminine,” said Dan Carlson, a sociology professor at Georgia State University and one of the authors of the new study. “But given the changes in attitudes over time and what people want, we weren’t so sure that conventional gender behavior was the only thing that turns people on anymore.

“There’s a lot of evidence that men who engage with their children and are involved at home are sexy, and women who are strong and independent turn men on,” he added.

And it turns out, he and his coauthors were right.

Carlson and his co-authors analyzed data on housework and sex from the 2006 Marital and Relationship Survey on a representative sample of 600 married and cohabiting low-to-moderate income couples with children.

They found that couples who shared the routine housework equitably had the most sex, about 7.74 times a month. They reported the highest level of satisfaction with that frequency, compared to the other couples, and also the highest quality of the sexual relationship.

Egalitarian couples were also substantially happier with the division of labor around the house than couples in the other arrangements. And women in egalitarian relationships were much more satisfied than their partners in the frequency of sex.

Sex and housework are huge indicators of a relationship’s stability. Other studies have found that tensions over the division housework, especially if women perceive that the division is unfair, are related to a greater likelihood of unhappy marriages and divorce. Women in fact, initiate divorce at least twice as often as men.

But now it may be men feeling that tension, as more men have taken over at home and may feel unhappy about it, especially after the Great Recession when so many lost their jobs and their partners became the main breadwinners. Carlson and his colleagues found that men in counter-conventional relationships, where they were doing most of the housework, reported the most dissatisfaction with their sex lives.

“Couples often find themselves in this arrangement, it’s not something they choose, which means they’re not always going to be satisfied with the housework arrangement,” Carlson said. “That dissatisfaction lowers the quality of their sexual intimacy.”

Couples in counter-conventional arrangements had sex two and a half times less per month than egalitarian couples, Carlson said, and were half as likely to be satisfied with their sex lives.

Yet for all the fair housework and hot sex, the study found that only 30 percent of all married couples reported being in egalitarian relationships, compared to 47 percent of cohabiting couples – who also reported having more sex than married couples.

Why so few? Forging egalitarian relationships was hard 20 to 30 years ago, when couples had no role models and no scripts, Carlson said. And it’s difficult for couples still. “Our institutions and our policies haven’t caught up with our attitudes. That’s why we’re still stalled.”