Data from the National Survey of Family Growth (NSFG) from 1982 to 2019, along with data from four waves of the Demographic Intelligence Family Survey (DIFS) from 2020 to 2022, point to a widening gap in fertility rates between more religious and less religious Americans.
In recent years, the fertility gap by religion has widened to unprecedented levels. But while this difference may comfort some of the faithful who hope higher fertility rates will ultimately yield stable membership in churches and synagogues, these hopes may be in vain. Rates of conversion into unfaith are too high, and fertility rates too low, to yield stable religious populations.
As a result, data from over 70,000 women surveyed from 1982 to as recently as 2019 can be used to estimate fertility rates for three broad groups of women: those without any religious affiliation, those with religious affiliation but less than weekly attendance, and those with at least weekly attendance.
It’s evident that birth rates among Americans who attend weekly have never dropped much below 2 children per woman, and as recently as 2008 were around 2.4 children each. Fertility among religious people did decline after the 2008 recession, but by 2017–2019, it was rising again.
Finally, fertility among non-religious women rose considerably from 1982 to 2005, then again from 2008 to 2012, showing a very different pattern than the one we see for religious women.
From 2010 to 2013, non-religious women had about the same birth rates as women who attended religious services less than weekly, before their fertility slumped through 2019.