The economist Justin Wolfers wrote a provocative post last month arguing that children are “inferior goods.”

For most goods — “normal goods” — people desire more of them as their income increases. But for inferior goods (like rice) people tend to consume less as they get richer and are able to afford more desirable and expensive goods (like steak).

Professor Wolfers used the chart below as one piece of evidence for this theory. It plots each country’s per capita income against how many children the average woman in that country has:

Gapminder Size of bubbles corresponds with size of population in each country.

As you can see, there is a strong inverse correlation between wealth and childbearing.

Another report, released Thursday by Gallup, may provides further support for Professor Wolfers’s hypothesis.

Since 1936, Gallup has been asking Americans about the “ideal number of children” they believe a family should have. And over the last 75 years, as Americans have gotten wealthier, more and more of them have said they desire fewer children:

As you can see, since 1977, most Americans have said having no more than two children is ideal. I should note also that Americans have been making good on those desires, and the fertility rate has fallen greatly over the last half-century.

Even within the populace today, preferences for brood size correlate with income, Gallup found.

Only a third of people with annual household incomes over $75,000 say they want families with three or more children. Of all Americans with income levels below $75,000, 44 percent say they want families with at least three children.

In Lake Wobegone all children may be above average, but across America, children appear to be inferior — at least economically speaking.

Article source: http://feeds.nytimes.com/click.phdo?i=3574827b6a16f16061b4811a84b56408