“OUR women know what to do and when,” crowed Vladimir Putin, Russia’s president, after a recent uptick in the country’s fertility rate. A fall in America’s, by contrast, produced gloom. Both reactions were absurd. The conventional measure of fertility is a poor guide to how many babies people produce.
Imagine a Lysistrata scenario in which nobody procreates for a year. The commonly cited “total fertility rate”—the number of births each woman would have, assuming that in each year of her reproductive life she had the average number of children for women of that age in the current year—would fall to zero. Once the sex strike ended, though, it would bounce back, perhaps even rising higher than before, if couples try to make up for lost time. The “cohort fertility rate”—the actual number of children born to each woman in her lifetime—would change little.
Life is not a Greek comedy, yet something like this has happened in many countries. Parenthood now starts later than it used to. The total fertility rate falls as births are delayed; once older parenthood becomes widespread, it rises again. The ebb and flow of babies is a...
from The Economist: International http://ift.tt/1HUECzz
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