Yesterday, Tyler Cowan mentioned in the Marginal Revolution blog that he wished books on urban areas “would spend more time discussing whether dense urban areas are simply a fertility trap.” I’m not going to write a book about it, but it may be one more reason why planners’ mania for density is a bad idea.
There appears to be a correlation between state fertility rates and land-use regulation aimed at increasing urban densities. Click image to go to a Wikipedia article on fertility rates by state.
A fertility trap, sometimes called a low fertility trap, is a situation where a nation’s birth rate has declined below the replacement rate of 2.1 children per woman. Within a generation, this leads to a reduction in the number of young people working, which means — in a country that has a social security system, as most developed countries do — the number of older people that each young person must support increases. Continue reading
