I am discussing about evolution theory with a philosophy student and she observes that wealthier families tend to have fewer children, which kind of goes against natural selection, i.e. the genes of smarter/healthier people do not necessarily pass along the generations.

Now I am thinking:

  • Is there really such a pattern? If yes,
  • Does it vary across different environments (e.g. developed vs developing countries)?
  • What is the economics explanation?

References to papers are very welcome.

I am not sure how to tag this question, feel free to edit.

  • 4
    $\begingroup$ Smarter has very little to do with wealthier. And I strongly recommend refraining from socio-biological speculation. $\endgroup$
    – 410 gone
    Nov 30, 2015 at 20:37
  • 3
    $\begingroup$ In a short time one of you will argue that idiocracy is real (see xkcd.com/603). But it is not. Intelligence is a welcome trait in all social environments. The phenomenon you describe may only result in fewer children bringing a good educational background from home. $\endgroup$
    – Giskard
    Nov 30, 2015 at 20:37
  • $\begingroup$ Again, we are just pointing out that you claim that wealth means smart/healthy. Let us cast aside this assumption. There are papers that deal with income and fertility. econ.yale.edu/~pschultz/cdp925.pdf $\endgroup$
    – Giskard
    Nov 30, 2015 at 20:48
  • $\begingroup$ This may help: en.wikipedia.org/wiki/Total_fertility_rate#/media/… $\endgroup$
    – paj28
    Nov 30, 2015 at 22:04

1 Answer 1


Population changes slowly over time but has large effects in the long-run. Here are some well-studied facts about fertility:

  • Before the industrial revolution, the rich had more surviving children than the poor.
  • The transition from stagnation to economic growth is accompanied by a demographic transition from high to low fertility.
  • Today, both within and across countries, rich and educated mothers have less children than poor and unskilled ones.
  • Most of the literature finds that the income of the father positively affects fertility, while the income of the mother negatively affects fertility.

Economists would stress that one explanation among others is Parents' income: Opportunity cost of child-rearing time is high for high income/education mothers. They are other reasons.

David de la Croix works on this topic and offers interesting lectures on Fertility, Education, Growth and Sustainability here. You will find references for the above facts and other reasons for the decline in fertility.

An academic reference is: De la Croix D. and M. Doepke, Inequality and growth: why differential fertility matters, American Economic Review, 93, 1091-1113, 2003.


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