Kara's on vacation this week, so we're bringing you an episode of another great Times Opinion podcast, 'The Argument.'

U.S. birthrates have fallen by 4 percent, hitting a record low. And it’s not just America — people around the world are having fewer children, from South Korea to South America.

In some ways, this seems inevitable. From an economic standpoint, there’s the expensive trio of child rearing, education and health care in America. From a cultural perspective, women have more financial and societal independence, delaying the age of childbirth. What might be troubling are the consequences on our future economy and what an older population might mean for Social Security.

This week, Jane Coaston talks to two demographers who have differing levels of worry about the news of our falling birthrate. Lyman Stone is the director of research at the consulting firm Demographic Intelligence, an adjunct fellow at the American Enterprise Institute, a research fellow at the Institute for Family Studies, a Robert Novak Journalism fellow and a Ph.D. student in population dynamics at McGill University. Caroline Hartnett is a demographer and an associate professor of sociology at the University of South Carolina.

You can find more information for all episodes at nytimes.com/sway, and you can find Kara on Twitter @karaswisher.