There are seven ways to divorce-proof your marriage.
Whatever the number, economist Enrico Moretti, from the University of California, has added another to the list: make sure your firstborn is a boy.
In a startling interview on Freakonomics Radio, Professor Moretti revealed that in marriages where the firstborn is a boy, there is less chance of divorce.
"Parents who have firstborn girls are significantly more likely to be divorced, and parents who have firstborn boys are significantly more likely to stay together," he said.
No, this interview was not recorded a hundred years ago; the interview was conducted just two weeks ago, and Professor Moretti’s research is based, among other things, on US census data.
"Fathers are significantly less likely to be living with their children if they have daughters rather than sons. This overall effect is fairly large ... We estimate that over a 10-year period, that accounts for about 50,000 firstborn daughters [in the US] who are living without their fathers."
That's not his only startling revelation; the statistics say that if the new parents aren’t married, they're less likely to marry if they have a daughter, rather than a son.
"The gender of the kid affects the probability of shotgun marriages," said Professor Moretti. "In particular, we found that for parents who are not married upon conception of the kid, those who learn that their future child will be a boy are more likely to marry by the time of delivery, compared to parents who learn that their future child will be a girl."
The economic impact of this gender bias isn't a trifling matter: Professor Moretti estimates that "for children in families with an absent father due to a firstborn daughter, family income is reduced by about 50 per cent."
Fathers are also less likely to seek custody of daughters rather than sons.
The preference for a boy is so strong that in families with a firstborn daughter, the probability of trying for a second child is significantly higher.
"Families whose firstborn is a boy seem to feel less of a need [to have another child], related to families whose first born is a daughter," Professor Moretti said.
Before we assume that these statistics indicate that parents value boys more than girls, it’s possible that what has been termed as ‘the daughter affect’ isn't caused by a gender bias; it may be that fathers believe that having a man around is more important for boys than it is for girls, and therefore they stay because they think they are needed as a role model.
But this may be an overly generous explanation, particularly in light of a 2011 Gallop poll which revealed that most Americans prefer to have sons.
When asked, "Suppose you could only have one child, would you prefer that it be a boy or a girl?", 40 per cent of respondents preferred a boy; 28 per cent said they preferred a girl. Just over a quarter (26 per cent) said it didn’t matter.
This preference was mostly driven by men - when looking at the answers given by women, it showed their preferences were evenly split.
The preference for boys has not changed since the Gallop poll was originally conducted back in 1941.
While Professor Moretti concedes that there are many factors that determine divorce or marital stability, the fact that the child’s gender is one of them shows a deep-seated cultural bias that, from the moment of conception, continues to value boys more than girls.
This article first appeared on Daily Life.