LONDON (RNS) A British university study suggests that people of strong faith can spread religion through a “believers’ gene” that is part of their DNA.

Cambridge University economics professor Robert Rowthorn theorizes a “predisposition toward religion” in a paper published in “Proceedings of the Royal Society B,” a prestigious journal of Britain’s Royal Society of scientists.

Rowthorn suggests that people with strong religious beliefs tend to have more children and that this, combined with a genetic predisposition to believe, can explain the expansion of religion.

The academic cites the World Values Survey in 82 nations from 1981 to 2004, which found that people who attended religious services more than once a week had an average of 2.5 children; those who never attended averaged only 1.67.

“The more devout people are,” Rowthorn wrote, “the more children they are likely to have.”

This, coupled with a “genetic endowment” that his theory ascribes to strong believers, could mean the spread of faith across the broad sweep of the population.

As one example of a rapidly growing religious community, Rowthorn cited the explosion of the Old Order Amish population in the United States, from 123,000 in 1991 to 249,000 in 2010.

In practice, Rowthorn said, many people leave their childhood religions behind, or marry outside them and have less children, thus slowing the spread of the “believer’s gene.”

But the genetic disposition remains so strong that “the religiosity gene will eventually predominate,” and a significant increase in religious believers should still be on the cards, Rowthorn suggests.