Daughters are more Likely to Endure the Stress of a Troubled Marriage

Though previous research has shown that couples with daughters are more likely to divorce than those with sons in the United States, officials from Duke University discovered another determining factor. They found that girls may be more likely than boys to survive in the womb throughout the stress of a troubled marriage.

"Many have suggested that girls have a negative effect on the stability of their parents' union," said Duke economist Amar Hamoudi, who co-authored the new study with Jenna Nobles, a University of Wisconsin-Madison sociologist, in a news release. "We are saying: 'Not so fast.' "

Hamoudi said that female embryos are typically hardier than male ones. For instance, from every age from birth to 100, boys and men die in greater proportions than girls and women-suggesting that female embryos may be better able to endure symptoms of stress created by relationship conflict.

For the study, researchers examined an analysis of longitudinal data from a nationally representative sample of U.S. residents from 1979 to 2010. Findings showed that a couple's level of relationship conflict at a given time also predicted the sex of children born to that couple at later points in time. Women who reported higher levels of marital issues were also more likely in subsequent years to give birth to girls, rather than boys.

"Girls may well be surviving stressful pregnancies that boys can't survive," Hamoudi said. "Thus girls are more likely than boys to be born into marriages that were already strained." 

"It's time for population studies to shine a light on the period of pregnancy," Hamoudi concluded. "The clock does not start at birth."

More information regarding the findings can be seen via the journal Demography.