We would all like to believe that we have children to satisfy motivations of a higher moral order. Perhaps it’s the urge to love somebody unconditionally, or even the deep genetic imperative to reproduce. But research suggests that more mundane cost-benefit calculations play a role in the reproductive decision. Specifically, one of the reasons we have kids is to provide income insurance, to pay for our keep when we get old.
Some of the most recent evidence of this link comes from Africa, where researchers have found that paying a public pension can reduce childbearing substantially. The study looked at fertility in the half-dozen or so countries that have broad based pensions. The pensions weren’t particularly generous –benefits amounted to as little as 15 percent of per capita GDP. Still, providing these benefits reduced fertility by somewhere between 0.5 and 1.5 children per woman.