Even so, proponents of child-friendly policies, left and right, are deeply skeptical that the government will prove willing to put family at the center of its laws—or that the government can change current birth-rate trends. Ultimately, a shared cultural commitment to the importance of children is the factor that will determine America’s baby-making future.

Across the developed world, birth rates are below replacement level, meaning women don’t have enough children to replenish the population. Pro-natalists argue that this will have devastating consequences. By contrast, they say, having kids has lots of upsides. “People want it. Society needs it. We want the economy to grow,” said Stone said in an interview.

At least in Europe and the U.S., birth rates tend to lag behind what women desire. According to data reported by the Pew Research Center in 2014, 40 percent of American women approaching the end of their childbearing years say they have fewer kids than they had wanted.

The argument that having more kids is good for society is a little bit trickier. Some environmentalists argue that population control is key to protecting the earth’s resources. Others say a childless lifestyle might be preferable to the life of a parent. Some philosophers even argue that it’s immoral to have kids at all.

Pro-natalists say societal well-being—and democracy itself—depend on Americans’ willingness to procreate. “It’s not that common that love is a policy argument,” Stone said. But “the most important part of human well-being is family.” And “that’s not a subjective statement,” he added. “That’s an objective one” supported by public-health literature.

Jonathan Last, The Weekly Standard’s digital editor and author of What to Expect When No One’s Expecting, takes a more somber view: If people in authoritarian societies have more children than citizens of liberal democracies, “over the long haul, those people inherit the earth,” he said. The economics of a shrinking global population could lead to chaos and desperate political acts, he predicted: “In the course of the next 50 or 100 years, you could wind up in a world that is unstable and unpleasant and illiberal.”

The economic case for more babies is fairly straightforward: More workers presumably yield more productivity. As Stone said, “There is no economy that has managed to knock out gangbuster growth with a declining population.” And a wild imbalance between populations of the non-working elderly and strapping young people can wreak havoc: “As governments raise taxes on a dwindling working-age population to cover the growing burdens of supporting the elderly,” wrote the journalist Phillip Longman in a 2006 essay for Foreign Policy, “young couples may conclude they are even less able to afford children than their parents were.”