Why do people keep having kids? After all, children cost their parents more in food and college tuition than they bring in by, say, working the family farm. And in developed countries where parents feel the financial pinch, birthrates have dropped accordingly.
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 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.