One thing I love about studying religion is that it impacts every aspect of social life. How people vote, where they live, what kind of jobs they pursue, are influenced in some way by their religious beliefs and behaviors.

One choice that is clearly shaped by religion is when (and if) adults have children and how large they want their families to be.

In the United States, the fertility rate in 2008 was 2.06 children per woman. In 2023, it’s projected to be 1.78 children per woman. Forty-nine out of 50 states had a lower fertility rate in 2020 compared to 2010 (North Dakota was the only one to buck the trend.)

Obviously, there are a ton of factors that lead to a drop in fertility. Economics is usually considered to be a leading culprit for a drop in fertility. The Great Recession is supposed to lead to an enrollment cliff in higher education in the next five years because people decided to delay pregnancy.

But here’s another explanation that may be playing a noticeable role in the drop in American fertility: the increasing secularization of the United States.

Judaism, Christianity and Islam all encourage their adherents to marry and have children. But lots of Americans don’t adhere to those faiths anymore. I wrote an entire book (actually two of them) about the rising number of Americans who reject religion entirely or, at least, organized forms of faith.

Does this actually matter, though? Do we see in the data a difference in parenting rates for atheists compared to Latter-day Saints, for instance?