A new study has challenged one of the most established and accepted standards in the social sciences - human fertility levels tend to decline as countries advance towards high levels of social and economic development.
It has shown a reversal of fertility decline in highly developed countries once they reach a certain level of wealth.
The study, conducted by Hans-Peter Kohler and Mikko Myrskyla from the University of Pennsylvania and Francesco C. Billari from the Universita Bocconi in Milan, is published in the current issue of the journal Nature.
For the study, the researchers looked at total fertility rate and the human development index, HDI, in 24 developed countries during a 30-year period.
The study showed that the well-established negative relationship between fertility and development has been reversing as the global population entered the 21st century.
While social and economic development continues to promote fertility decline at low and medium levels of HDI, at advanced HDI levels further development can reverse the declining trend in fertility.
Now, HDI is positively linked to fertility among highly developed countries.
This reversal of fertility decline as a result of continued economic and social development has the potential to slow the rates of population aging, thereby ameliorating the social and economic problems that have been associated with the emergence and persistence of very low fertility.
"This study provides some 'light at the end of the tunnel' for countries that were concerned about population aging and population decline as a result of very low fertility rates," said Kohler.
"This is a surprising new empirical finding that will almost certainly generate additional research to better understand the underlying mechanisms of fertility change and possible policy responses to low fertility," Kohler added.