The way couples divide up the household chores may give a clue as to whether they are likely to have a second baby.
Contraceptive or fertility boost?
US scientists have discovered that 81% of couples in which the husband does at least half the housework will have a second child.
This drops to 74% if the woman does the bulk, the Population Development and Review journal paper says.
However, those who split the chores with no clear plan of action are least likely to have a second child.
The researchers from Brown University studied 265 married couples in which both partners were employed.
The husbands and wives were asked to report how much time they and their spouses spent per week on nine common household tasks, such as cooking, shopping and cleaning.
Modern families, those in which the women did less than 54% of the housework, were highly likely to have a second child within the next five years.
Similarly, more traditional couples, where the woman did more than 84% of the housework, frequently went on to have a second child.
Couples who had not worked out how to divide the work were the least likely to have a second child.
For example, when the woman did between 54% and 84% of the housework, the likelihood of the couple having a second child went down to 55%.
The study authors suggested that these couples found it hard to strike the right balance between work and home life.
As a result, the couples might chose to opt out of growing their family, they said.
Lead researcher Berna Miller Torr explained: "These couples may well struggle with the balance between work and family, choosing less family as a result."
Christine Northam, a counsellor for Relate, said more and more, couples are both working.
"I get the impression that in order to maintain a middle class lifestyle these days it is necessary for both husband and wife to work.
"The birth rate is falling slightly, so you could say because people are so pressurised they are less likely to have children."
She said some couples may decide it is better for one half to stay at home and take on all of the household tasks.
"If one of them is taking complete responsibility for the housework it means the other one doesn't have that on top of everything else.
"It may well indicate that one of them had decided to stay home and look after the family, in which case maybe for that couple having a family is more of a priority than working," she said.
But she thought couples who work together as a team tend to be more together as a couple.
"If there is teamwork then that can be an indicator of a successful relationship where they can negotiate tasks and responsibilities."