Economists Gordon Dahl (at the University of Rochester) and Enrico Moretti (at UCLA) discovered the following facts in 2003: In the United States, the parents of a girl are nearly 5 percent more likely to divorce than the parents of a boy. Illustration by Barry Falls 
 
 Parents of girls are 5 percent more likely to divorce than parents of boys. And, they found, an unmarried couple is more likely to marry if they learn their unborn child will be a boy than a girl. Dahl and Moretti have summarized attempts to explain their facts as follows: Sons may either improve the quality of married life or worsen the pain of divorce (perhaps by becoming more distraught when the father leaves). After all, she says, nearly three-quarters of all divorces involve a wife leaving her husband, so the question is not why do men stay for boys, but rather why mothers of daughters are divorcing more than mothers of sons. Noting other studies, which show that adult sons who live at home increase the “chore” burden on their parents while adult daughters decrease it, and also that “females offer more and better social support than men,” she concludes: 
 
 … wives with daughters are less likely to stay with their husbands because they know that with a girl, they’ll never be lonely or without help. Thus, they may be less willing to tolerate any bad behaviors from their husbands (and less willing to stay married) because they don't need their husbands as much. This idea could even explain why couples expecting a girl are less likely to marry: A woman carrying a girl anticipates that she won't need a husband.
– Sociologists have puzzled over an odd stat for years: Parents are more likely to divorce if they have girls instead of boys. The New York Times parenting blog today takes note of a new theory by a Notre Dame psychologist: Women who have daughters don't need a husband as much "because they know that with a girl, they'll never be lonely or without help." These women "may be less willing to tolerate any bad behaviors from their husbands (and less willing to stay married)," writes psychologist Anita E. Kelly in Psychology Today. "This idea could even explain why couples expecting a girl are less likely to marry: A woman carrying a girl anticipates that she won't need a husband." As they say, girls rule, boys drool.