In a dramatic shift in attitudes from just 40 years ago, most modern couples want to share the duties and rewards of work and family equally. However, this is particularly difficult for new parents in the U.S. in light of limited governmental support and persistent traditional gender norms. The U.S. offers inadequate paid parental leave and few options for cutting hours at work, while the cost of quality infant child care is exceptionally high. Thus parenthood is especially challenging for U.S. couples—the majority of whom are dual-earners who strive to achieve a work/family balance.

We studied 182 different-sex couples who were expecting their first child. Most were professionals who were well-positioned to equally share housework, parenting, and paid work responsibilities due to their high levels of education and the fact that both partners were working full-time. During the last trimester of the woman’s pregnancy and at 9-months postpartum, we had these men and women keep time diaries, recording every activity they engaged in during a 24-hour workday and non-workday. We also surveyed them about their own attitudes and perceptions of their division of labor at the beginning of our study and again when their child was nine months old.

In our initial interviews, these couples told us that they believed in sharing household responsibilities equally—and our time diaries confirmed that in fact they successfully did so before the baby was born. On average, both women and men perceived they were doing about 60 hours of work, including paid work and housework, per week. The time-diary data we collected, which are more accurate than retrospective survey data on how people spend their time, supported their perceptions. Women and men reported about 15 hours of housework and between 42 and 45 hours of paid work per week. This means that before the babies were born, most couples had achieved a balanced division of labor.

When we surveyed these expectant couples about their future, most said they wanted to continue to equally share housework and childcare after their baby was born. More than 95 percent of both men and women agreed that “men should share with child care such as bathing, feeding, and dressing the child” and that “it is equally as important for a father to provide financial, physical, and emotional care to his children.”

We surveyed the couples again when their babies were 9 months old, asking them how much time they were now spending in paid work, housework, and child care. Both the men and the women reported that they were each performing 90 hours of work per week, including housework, childcare, and paid labor. That is, they both felt that parenthood increased their workload by about 30 hours a week. Men reported that they were doing 35 hours of housework, 15 hours of child care, and 41 hours of paid work per week. Women reported that they were doing 27 hours of housework, 28 hours of child care, and 35 hours of paid work per week.When their babies were 9 months old, both parents felt that parenthood had increased their workload by about 30 hours a week. Their time diaries revealed that their perceptions did not match their realities.

This time, however, their perceptions did not match their reality. Using our detailed time diaries, we were able to construct a much more accurate account of their work weeks than they retrospectively estimated in the surveys, and the results were quite different than the parents reported to us. Women performed 15 ½ hours of physical child care per week, including physical child care (changing diapers, feeding the baby)—12 hours less than they thought they were performing. They also performed 6 hours of child engagement (playing and reading with the baby), but we did not survey them on their perceptions of the time spent engaging with their child. Women spent 42 hours doing paid work—six hours more than they thought they spent in their jobs—and 13.5 hours doing housework—14 hours less than what they thought they were doing.

Men did about 10 hours of physical child care—5 fewer hours than they thought they were doing. Men put in 46 hours of paid work—5 hours more than they thought they put in at work. Their estimates of housework diverged especially sharply from what they recorded in their time diaries. The time diaries revealed that on average the men did just 9 hours of housework—only one-fourth as much as they thought they were doing (men estimated that they performed 35 hours of housework).

In other words, on average, 9 months after the transition to parenthood, women added 22 hours of childcare (physical and engagement) to their work week while doing the same amount of housework and paid work as before. Men added 14 hours of childcare to their work week, but did 5 fewer hours of housework after the baby’s birth.

Before the baby was born, a man’s average work week (paid and unpaid hours combined) was three hours longer than his partner’s. But after the birth of their child, the man’s total workload averaged about 8 and half hours less per week than his partner’s. Women’s total weekly workload increased from 56 to 77 hours across the transition to parenthood, while men’s increased from 59 to 69 hours.

Thus, over the course of a year, our calculations indicate that parenthood increased women’s total workload by about 4 ½ weeks of 24-hour days, whereas parenthood increased men’s total workload by approximately 1 ½ weeks—a 3-week per year gender gap.

Parenting an infant is a time-consuming activity that changes the rhythm of daily life. But it is especially fascinating that new parents, and particularly men, perceive the work of parenthood to be even more time-consuming than it actually is. Parenthood does result in increased work, but men and women are not actually working 30 hours more per week after their babies are born. Women come close—working 21 more hours per week after the birth of their first child. Men do much less than they—or their wives—perceive: parenthood only adds 13 hours of work for men.Parenthood is a time-consuming activity that changes the rhythm of daily life, but new parents perceive the work as even more time-consuming than it actually is.

It is possible that fathers will become more involved in physical childcare and engagement as the babies grow into running and talking toddlers. But we would argue that men and women should openly confront the workload inequities that develop in their child’s first nine months because renegotiating the division of labor once routines are established is really difficult.

Furthermore, if these inequities are not addressed early, some women may feel compelled to leave or reduce their hours in the labor force, diminishing their own career opportunities as well as the family’s ability to save for college and retirement. In turn, women’s “opting out” of paid work may result in men’s opting out of even more family work. Thus, children may miss out on the benefits of involved fathering for their social, emotional, and cognitive development.

New parents who desire equality over the long haul might be well-advised to address rather than deny the inequalities that develop in the early months of parenthood. Couples who recognize that the transition to parenthood is a “magic moment” and split family work evenly will enjoy the benefits—more satisfying relationships and more economic resources and security.