From Psychology Today:
Conventional wisdom dictates that people become parents because children bring joy. But do they really? For scientists studying the subject, simply correlating parenthood and happiness can’t answer this question, since happy people might be more likely to have kids to begin with. But a recent study that compared happiness levels in adult identical twins–some of whom are parents and some who aren’t–may be getting to the bottom of the issue.
The study, headed by sociology professor Hans-Peter Kohler of the University of Pennsylvania, found that people with children are, in fact, happier than those without children. But such happiness gains differ for mothers and fathers.
In comparing identical twins, Kohler found that mothers with one child are about 20 percent happier than their childless counterparts; and while fathers’ happiness gains are smaller, men enjoy an almost 75 percent larger happiness boost from a firstborn son than from a firstborn daughter. The first child’s sex doesn’t matter to mothers, perhaps because women are better than men at enjoying the company of both girls and boys, Kohler speculates.
Interestingly, second and third children don’t add to parents’ happiness at all. In fact, these additional children seem to make mothers less happy than mothers with only one child–though still happier than women with no children.
“If you want to maximize your subjective well-being, you should stop at one child,” concludes Kohler, adding that people probably have additional children either for the benefit of the firstborn or because they reason that if the first child made them happy, the second one will, too.
This isn’t the first bit of psychological evidence suggesting that happiness and children are inversely correlated, at least when your happiness is evaluated on a moment-by-moment basis. As Daniel Gilbert notes, “The only known symptom of the empty-nest syndrome is increased smiling. Careful studies of how women feel as they go about their daily activities show that they are less happy when taking care of their children than when eating, exercising, shopping, napping, or watching television.” According to the self-reports of parents, looking after the kids is only marginally better than mopping the floor.