A fascinating new study published by the National Bureau of Economic Research finds that boys from ‘disadvantaged’ families do worse than girls. The disadvantaged families are predominantly headed by a single female parent.
We find that, relative to their sisters, boys born to disadvantaged families have higher rates of disciplinary problems, lower achievement scores, and fewer high-school completions.
[E]mployment rates of young women are nearly invariant to family marital status, while the employment rates of young adult men from non-married families are eight to ten percentage points below those from married families at all income levels.
In other words, all else equal, non-married status matters only for boys, not for girls. The authors, as well as most commenters on the study, conclude that the sex gap in success must be environmental and not genetic. Apparently, growing up without a father at home is somehow particularly damaging for boys, but not for girls, perhaps because mothers devote relatively more attention to their daughters and sympathize more with the needs of their daughters. In any event, nobody is really quite sure of the reasons, but one way or another, fathers are more important to raising boys than girls. This result supports the longstanding assertion of social conservatives that boys need fathers.
Observers reject a genetic argument in favor of environment, I suspect, because of the study’s focus on siblings. The boys and girls in the study should not differ much genetically because the siblings share at least one, and often two, parents.
An awful lot of research, however, has shown that life outcomes have a strong genetic basis. I’m not convinced, therefore, that the results of the study in question cannot have a genetic explanation.
In particular, life success has been shown to correlate strongly with I.Q. and the personality trait of ‘conscientiousness,’ which is heritable. Conscientiousness is the only one of the Big Five personality traits that predicts career success.
[A]fter general mental ability is taken into account, the other four of the Big Five personality traits do not aid in predicting career success.
And here’s a definition of conscientiousness.
[Conscientious people] exhibit a tendency to show self-discipline, act dutifully, and aim for achievement; they display planned rather than spontaneous behavior; and they are generally organized and dependable.
Men lacking in conscientiousness seem exactly the sort of fathers unable to form stable families and to fulfill fatherly duties. Since they are not dutiful or dependable, the mothers cannot rely on them, and end up heading the household themselves.
Now, I am not a geneticist, but I see no reason why fathers could not pass on their lack of conscientiousness to their sons relatively more than their daughters. Maybe I’m mistaken, but there could be a set of genes that undermine male conscientiousness, but have a relatively muted effect in females. If in terms of heritable conscientiousness, if boys align more with their fathers and girls with their mothers, then genetics can explain the result that boys from broken homes do worse than girls.
If so, then social conservatives might not be correct about the environmental role of fathers. But the age-old wisdom that women should not have kids with irresponsible men would still hold true.