According to Caplan, a professor at George Mason University, the major mistake that parents (or prospective parents) make is overvaluing the present. This is a common enough error. Workers in their twenties and thirties don’t save enough money for retirement because it seems such a long way off. Then their sixties roll around, and they wish they’d spent less on S.U.V.s and HDTVs and put more into their 401(k)s.
Couples, he argues, need to think not just about how many children they might want now, when they have better things to do than microwave Similac, but how many they will want to have around when they’re old and lonely and watching “The View.” Caplan recommends what he calls the “take the average” rule:
Suppose you’re thirty. Selfishly speaking, you conclude that the most pleasant number of children to have during your thirties is one. During your forties, your optimal number of kids will rise to two—you’ll have more free time as your kids assert their independence. By the time you’re in your fifties, all your kids will be busy with their own lives. At this stage, wouldn’t it be nice to have four kids who periodically drop by? Finally, once you pass sixty and prepare to retire, you’ll have ample free time to spend with your grandchildren. Five kids would be a good insurance policy against grandchildlessness.
Caplan does the math and concludes that in this case “the best number of kids is three.”