On the surface, there is no religious component to the following question: "Why do some people choose to have children, while others do not?" The same thing is true if you ask, "Why do some people choose to have more than 2.1 children, while others do not?"

But if you know anything about polling linked to demographics, you know that it's impossible to answer those questions in real life -- in a majority of cases around the world -- without running into religious beliefs and practice. Look at it this way, if one Catholic family has one child and another has seven, the odds are very high that family No. 2 goes to Mass way more often than family No. 1.

Several years ago, The Weekly Standard (yes a conservative journal) did a highly fact-driven think piece -- "America's One-Child Policy" -- that contained the following paragraph that remains as relevant today as when it was written:

... (In) a world where childbearing has no practical benefit, people have babies because they want to, either for self-fulfillment or as a moral imperative. "Moral imperative," of course, is a euphemism for "religious compulsion." There are stark differences in fertility between secular and religious people.

The best indicator of actual fertility is "aspirational fertility" -- the number of children men and women say they would like to have. Gallup has been asking Americans about their "ideal family size" since 1936. When they first asked the question, 64 percent of Americans said that three or more children were ideal; 34 percent said that zero, one, or two children were ideal. Today only 34 percent of Americans think that a family with three-or-more children is ideal.

So here is the thesis statement that I think, on many stories linked to contemporary religion (think coverage of the declining number of Catholic priests in North America), journalists need to think about.