‘It would be crazy to have children if they weren’t so damned important,” Jonathan V. Last writes in What to Expect When No One’s Expecting: America’s Coming Demographic Disaster. But he notes that “pets now outnumber American children by more than four to one.”

“America’s fertility decline was not caused by a grand conspiracy to eviscerate the family,” he explains. “Rather, it’s been the result of a thousand evolutions in modern life. Many of these changes (the decline in infant mortality; the liberation of women into the workplace) have been enormously beneficial to us as a society. Some of them (the epidemics of divorce and cohabitation) have not. But even the changes we think of as beneficial have, as ancillary effects, created roadblocks to family formation. They delayed marriage and childbearing, or increased the cost of children, or decreased the return on that investment.” Last talks about his demographic warning in an interview with National Review Online’s Kathryn Jean Lopez.

KATHRYN JEAN LOPEZ: Clever title, but what business is it of any of us who’s expecting and who’s not? It’s a matter of choice, and who wants to bring a child into the world to pay our bills anyway?

JONATHAN V. LAST: That’s totally true. And I celebrate choice. Really — I do. I’ve got three kids and one of the great blessings of parenthood is that it cures you of any sentimentality about children. So anyone out there who doesn’t have kids, or doesn’t want them, I say, Godspeed. Remember me fondly the next time you’re taking a quick weekend getaway to London or going to the movies on a weeknight.

I say this pretty explicitly in What to Expect: Please don’t construe any part of the book as me telling you to have kids.

All of that said, children are — as high-minded economist types will note — both public and private goods. And society can’t function very well, or for very long, without a certain number of them being born. So whatever people decide to do at the individual level, there are macro effects to consider. I would just note that it’s a little weird that certain types of people are happy to consider the macro effects of individual behavior when it comes to smoking, or drinking soda — but say that we’re not allowed to notice these things when it comes to kids. I mean, it’s only the entire future of Western civilization we’re talking about.

LOPEZ: How is it that “fertility is shaping nearly everything in our national conversation”?

LAST: My hero Phil Longman once wrote that demography is like the tectonic plates shifting underneath the earth’s crust, determining the scope of the possible. I don’t think I can really improve on that metaphor. But just as a quick sample list, it’s just true that you cannot fully understand Medicare, Social Security, immigration, defense spending, the foreign challenges of Iran and China, the housing bubble, or the polarization of American politics without taking account of demographics.

LOPEZ: What do you have against yoga studios and pet boutiques?

LAST: I’m not against yoga studios or pet boutiques. In fact, without yoga studios, we would not have come up with one of the great inventions of the last century: yoga pants.

I just find the evolution of these kinds of lifestyle markers interesting. If you took a dog-lover from 1965 America and dropped him into the modern pet-fancy culture — with doggie car insurance and organic pet-food bakeries and kennels that built tiny houses with air conditioning and TVs for the pooches — he would probably think the world had gone insane.

By historical standards, our current fascination with pets is unusual. And hence interesting.

LOPEZ: Are we all going to become Florida Nation?

LAST: Oh yes. If current projections hold, by 2050 the population of Americans over the age of 65 will be greater than the population under the age of 14. We will be Florida. And Florida might look like Japan, where last year people bought more adult diapers than they did diapers for babies.

LOPEZ: Why shouldn’t we trust anyone over 65?

LAST: Because [looks over both shoulders] they’re Baby Boomers.

I kid. We’re in a serious enough demographic bind that we’re all going to have to work together to figure out a way to make this thing work. The thing is, when your fertility rate is sub-replacement, you enter a zero-sum game where either older folks aren’t going to get the benefits they were promised or young workers are going to face much steeper tax rates. How the politics of this issue resolves over the next 20 years will be one of the most interesting stories around. Will older Americans relinquish some of their claims? Will younger workers volunteer to pay more? Will there be some grand bargain? The truth is, no one knows how it will end. We just know that something has to give.

LOPEZ: Why do you point to Poland?

LAST: No real reason. Poland is just one of the interesting demographic case studies from Eastern Europe. You could just as easily look at the Czech Republic or Hungary.

But I like Poland because I’m a good Catholic boy and it gave us John Paul the Great.

LOPEZ: What’s the actual good news from Georgia?

LAST: Georgia is the only known example of a country recovering from lowest-low fertility to near the replacement rate. And the way they did it will shock you. When you read the book.

Short version: The patriarch of the Georgian Orthodox church, Ilia II, stepped in and volunteered to baptize all third-born children. The Georgians are really into their church. So they started having more babies. It’s pretty neat.

LOPEZ: Whose fertility do you worry about the most?

LAST: The people who want babies. For all the fashionable talk about how family life has gone out of style and how people don’t want kids anymore, the research is pretty clear: When demographers calculate America’s “ideal fertility rate” — that is, the number of children people say they’d like in a perfect world — that figure has been a pretty constant 2.5 for almost two generations.

Put that 2.5 ideal rate next to our 1.9 actual rate, and what you see is that while many people may not want children — which is fine! we celebrate your choice! — that is not the median American experience.

So what we have here is a persistent, generations-long gap between ideal and achieved fertility. This suggests to me that the solution isn’t arguing or trying to bribe people who don’t want kids — leave those nice folks alone! No, the solution is finding ways to help the people who do want kids achieve the families they desire.

LOPEZ: Why does your outline of historic demographic transitions matter?

LAST: Knowledge is its own reward. Plus, nothing makes you King of the Party like being able to dazzle your friends with a Brief Population History of the World.

LOPEZ: I thought you were a conservative, why does capitalism deserve only two cheers?

LAST: Did I say two cheers? I meant one cheer. Take that, Mitt Romney. We are the 47 percent!

Look, capitalism is the least bad system of economic organization and it has been responsible — over the long haul — for an amazing array of good outcomes. It has lifted masses of people out of poverty and into freedom and made their lives better in ways that are, literally, innumerable.

But the fact that capitalism has, on balance, good outcomes in the very long term shouldn’t blind us to capitalism’s short-term failures — which are often quite spectacular.

Take parenting, for instance. We have a system right now in which children could reasonably be construed as a marker of social failure. On average, people with higher levels of education and higher incomes have fewer children. And the costs of children — it’ll run you about $1.1 million to raise a middle-class kid through college — are such that to some degree, people become more economically successful by not having them.

If we were all Homo economicus, rational capitalism would never be able to suffice as an argument for having children. Yet, as we said up top, children remain both private and public goods. Here, then, I would suggest, capitalism fails us when it comes to providing right reason for pursuing the particular good of children. To cross that bridge, you need something else. Something I would suggest supersedes even capitalism as a guiding precept.

But then I already told you I was a good Catholic boy, and I don’t want to belabor the point. I’ll just say that there are greater things in heaven and earth than the free market.

LOPEZ: You note that religion helps demography. Further, you write: “Religion helps marriage and marriage helps fertility — the end result being that religiosity winds up being an even better predictor of fertility than either education or income. And as Americans have become more secular, they’ve cut back on having children. The good news is that while each of these three worlds — marriage, church, and fertility — is incredibly complicated, the interplay among them is somewhat straightforward. The bad news is that these realms are so foundational that it’s difficult to see how society might consciously nudge them in a positive direction.” You then go on to say that “something like the balance we had in the 1950s would be dandy.” So you just want to turn back the clock?

LAST: Yup. But let’s be modest. How about we turn it back just to a time when the federal government wasn’t forcing religious institutions to violate their consciences by providing contraception, sterilization, and abortifacients? I’d be happy to settle for there not being overt hostility on the part of government.

LOPEZ: Do you really need a “How to Make Babies”? We know how to do that, don’t we? Maybe if we didn’t consider medicating fertility the norm?

LAST: Look, I was as surprised as anyone else. I had always thought that it happened only when you took a date to see The Dark Knight.

LOPEZ: How does the “Social Security regime” distort “the ‘market value’ of children” and force the fertility rate down?

LAST: For a long time, one of the functions of children was to take care of parents in their dotage. Uncle Sam does that now. Moral hazard. Game. Set. Match.

The research on this suggests that Social Security and Medicare depress the American fertility rate by about 0.5 kids.

And as everyone knows, half-kids are the best kids.

LOPEZ: What’s been the most interesting feedback thus far? The most challenging?

LAST: A writer at the Huffington Post claimed that I’m part of “The Baby Matrix.” Or something. I couldn’t tell if I was Neo or Agent Smith. From her tone, probably Agent Smith. Still, that’s not nothing.

There hasn’t been much challenging feedback, but that’s because at bottom, What to Expect isn’t a particularly controversial book. It’s heavily based on data and research, and these data and research come not from me, but from the demography establishment. Most of those guys and gals — whom I love, by the way — are pretty liberal in their politics. It’s just that among the people who do this stuff for a living, there isn’t a whole lot of daylight between “conservative” demographers and “liberal” demographers.

The only people who seem shocked by this stuff are what I think of as lay liberals, who don’t follow the research closely.

LOPEZ: What do you find most dire?

LAST: The abortion rate in Russia. It’s the most depressing thing I’ve ever seen. So depressing, that I won’t even write it down here.

LOPEZ: What do you find most encouraging?

LAST: In Germany, they have a state-run program to take prostitutes and train them to become elder-care nurses — because their fertility rate is so low that they’re running out of young people to take care of all the old folks.

So even in the midst of social tragedy, there is hope. At least for old, German men.

LOPEZ: You have a sense of humor in the book. Was that hard given the topic?

LAST: One of the joys of being a grown-up is that no one assigns you book reports — so people don’t have to read books that aren’t fun. But it is important to read books that teach you things, kind of intellectual spinach. My writing mantra for What to Expect was “deep-fried spinach, wrapped in cotton candy.”

— Kathryn Jean Lopez is editor-at-large of National Review Online.