Families gathering for Father's Day will celebrate dads' contributions to their children's lives, but new research shows a surprising effect that kids can have on their fathers, too.
Two University of Washington economists have discovered that American men work longer hours after having children ñ and the effect is significantly greater when they have sons than when they have daughters.
The study, to be presented June 22 to the World Conference of the European Association of Labor Economists/Society of Labor Economists in Milan, leaves it to the authors' next phase of research to nail down the reasons for the gender disparity.
"We can only guess that having a son increases the value of marriage and family for men," said Shelly Lundberg, UW economics professor and one of the authors. Thus, the theory goes, fathers of sons knuckle down more on the job to ensure the family's security and well-being.
But even with the causes still unclear, the study breaks new ground by documenting the effect of parenthood on menís work life ñ and the significant difference between fathers of boys and girls.
The researchers used data from the U.S. Panel Study of Income Dynamics on more than 1,200 men, from 1968 through 1993. They found that the birth of a first son generated an average increase in a man's work time of 84 hours every year after the boyís birth ñ the equivalent of more than two additional weeks on the job. Men added only 31 hours of work after having a daughter.
As for the mothers, the economists found, as in other studies, that women earn less and earn less per hour after having children. That was true whether the child was a boy or a girl.
If fathers value their sons so much, why spend more time at work?
The increase in fathers' work hours appeared to come, not at the expense of family time, but of leisure pursuits. Other studies have shown that fathers spend more time at home with sons than with daughters.
The UW economists initially did not focus, however, on children's gender. They were hoping to build on previous studies describing how women's earnings and work hours decline when they become parents. The UW researchers documented the opposite effect of parenthood on men's earningsñ a "fatherhood premium" that raised men's hourly wages by about 4.5 percent every time they fathered a child.
But when Lundberg and co-author Elaina Rose, an assistant professor of economics, also reviewed the data by the offspring's gender, they found a significant gap between fathers of boys and girls that left them astonished.
"This type of finding is not unusual for, say, rural India," said Rose, who has studied the economics of gender and the family in Asia. "But I was absolutely shocked to see such a strong effect for the U.S. Gender bias is apparently alive and well, here, as well."