Birth rates are decreasing and it appears the reason behind that is increased secularization and/or hostility towards religion according to Baylor University professor Philip Jenkins. In a recent live stream, he explained how demography has played a role in these religious beliefs.

Jenkins shed more light on the correlation when he spoke on the “Fertility and Faith: A Conversation with Phillip Jenkins.” Philips is a professor of history and co-director of the program on historical studies of religion at the university.

The difference in religious beliefs is something he pointed out during the live stream. He shed more light on the religious beliefs of certain regions like Africa where the fertility rate is high. More to that, he also explained how this would be a derivative factor in separating people from faith communities and religious institutions. Hence, this serves as an insight into how societies around the world become more secularized.

"We measure change in a society through fertility," Jenkins said. "There is a close correlation between a fertility rate of a particular society or nation and the level of religious involvement or participation in that society."

Beyond Africa, secularization is on the rise, particularly in Europe. Depending on how one views this, it could address the problems faced by families having a lot of offspring but places religion in a spot. Some may end up being hostile to religion, some even being defiant on what religion tells them to do with their lives.

"You might argue that as you take children out of the picture there are far fewer links connecting families and people to institutions. ... Take children out of the religious picture and see what happens," Jenkins said.

One reason seen for the shift to secularization is the belief that there would be a population explosion at one point. According to Jenkins, what resulted was the exact opposite.

"To put it crudely, we have lost 2 billion people since then [the 1970s] from what was projected versus what we've actually got," he said. "This is happening because so many people in Latin American and Asia gave up having traditional 'third world' population growth rates and suddenly became Danish."

In the United States, secularization and fertilization have also dropped significantly. More to that, people who no longer affiliate with any particular faith have grown sharply. They are better known as “nones.”

"The proportion of nones in the U.S. has risen very dramatically in the last 10 to 15 years in exactly the same period that the fertility rate has dropped. And the three largest religious communities in the U.S. right now are evangelicals, Catholics, and nones. And within just a year or two, the nones are going to be the largest of those three groups. That is a stunning change in a very short time," Jenkins said.

When one talks about fertility, the immediate thing that comes to mind is sperm counts. As BBC pointed out, this has nothing to do with the falling numbers. Rather it is attributed to something else.

The number of women now opting to pursue a career and resort to contraception has been reasons behind it. Tied up to that, women are now choosing to have fewer children and raising a family depending on how they can manage their own families.

In the 1950s, women averaged 4.7 children at that time. Those numbers have dropped to about 2.1. While family planning comes to mind, it also means that the size of the population anywhere is starting to fall. Figures explaining this can be found at the Lancet.