Sharing child care responsibilities is associated with a higher quality of relationship, according to the study.
Sociologists at Georgia State University analyzed data obtained from the 2006 Marital Relationship Study reflecting the opinions of 487 heterosexual couples.
Their findings are to be presented at the 110th Annual Meeting of the American Sociological Association.
For the study, the researchers grouped the participating couples - all of whom had children - into three different categories; one group where the women did most or all of the child care, one group where the men did most or all of the child care and one group where child care responsibilities were more or less shared.
Relationship quality was assessed by reported relationship satisfaction and conflict, and the researchers also examined how often couples had sex and how they felt about it.
The lowest quality relationships and sex lives were reported when women were responsible for most or all (at least 60%) aspects of the couple's child care.
"The important point to be made is that when we're looking at child care, the difference that we find is really between arrangements where the mother is largely responsible for child care and everything else," says study co-author Daniel L. Carlson, an assistant professor of sociology.
When men took on the majority of child care responsibilities, relationship quality, sexual frequency and satisfaction with sexual frequency were just as high as with couples with shared child care responsibilities.
However, in relationships where men were responsible for the majority of child care, although women reported the highest overall satisfaction with their sex lives, men reported the lowest overall satisfaction with theirs.
Despite this, Prof. Carlson concludes that being an engaged father is important to men.
"If it weren't, we wouldn't see such a high level of satisfaction," he says. "It suggests that father engagement and sharing child care with one's partner is important to both sexes."
Future research will examine why sharing leads to positive results
Child care was defined within three dimensions in the study: physical/emotional child care, interactive child care and passive child care (supervision and monitoring). The researchers also measured child care by looking at four distinct tasks: rule making, rule enforcing, giving praise and playing with the children.
The researchers believe that these measures of child care were a limitation of the study, especially with regards to physical child care tasks.
"We only had one physical task, and that task revolved primarily around playing with the child, including sports and games, but nothing about who feeds or bathes the child," Prof. Carlson admits. "The latter physical, instrumental tasks have traditionally been the responsibility of women."
Another limitation of the study was that no same-sex couples were studied.
Prof. Carlson says that subsequent research will focus on uncovering the mechanisms to explain why couples with more shared child care responsibilities reported higher quality relationships and sex lives.
"We are trying to understand what it is about sharing that couples view so positively," he concludes.
A recent study suggests that relationship satisfaction could also be boosted by the practice of sexting, with higher levels of sexting associated with greater sexual satisfaction and relationship satisfaction.
The study also revealed that more than 8 out of 10 people admitted to sexting over the past year, indicating that the practice may be more common than previously thought.