What is the optimal number of children to have?

Photo of my son Quinn at 6.5 months taken by his grandpa, Red Taylor

If you're a parent seeking to maximize your own happiness, there's some research to suggest that one is the optimal number of children to have:

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.

(HT: Ross on Sullivan's Daily Dish) Also, the happiness gains are not necessarily immediate:

What seems to happen over time, says Kohler, is "you look forward to having a child, then you have it and find it really difficult and your happiness dips, and then you see a substantial gain." Overall, he says the lesson from the study is that "just having reproduced at least once seems to be the crucial aspect of providing the happiness gain."

Does that "substantial gain" in happiness come once sleep deprivation ends? I wouldn't be too surprised. (Quinn's been a bit erratic sleep-wise of late, and is currently resisting a nap most vociferously).

But maybe for one's long-term happiness, one should have more kids than one wants now so that when you're old you have more visits from your kids and more grandkids:

Basic microeconomics recommends a simple strategy. Have the number of children that maximizes average utility over your whole lifespan. When you are 30, you might feel like two children is plenty. But once you are 60, you are more likely to prefer ten sons and daughters to keep you company and keep the grandkids coming. A perfectly selfish and perfectly foresighted economic agent would strike a balance between these two states. For example, he might have four kids total - two too many at 30, six too few at 60.

Of course, there are other considerations than one's own happiness to think about. What about the happiness of your parents, who might want grandchildren? On the other hand, maybe from an ecological point of view, you shouldn't have any children, as any child brought up in this society will consume an enormous amount of resources. On yet another hand, it seems ecologically OK to replace yourself and the other parent, so maybe it's environmentally OK to have 2 children. Some people could have 3 children, because not all children will reproduce themselves. But who gets to decide who gets to have 3? And who's to say we won't soon have a more ecologically sustainable society (we better or we're in big trouble), where such considerations won't be as pressing?

Looking at it from another angle, what better gift can you bring to the world than a good, moral person who might contribute to solving the worlds problems (including ecological sustainability)? So maybe you should have as many children as you can bring up well. But how well do you have to bring them up to balance out their potential negative environmental impact? And what if you bring them up well but they turn out to be bad, anyway?

This is all very interesting. My peer group is facing these questions right now in a very concrete way.