Why Americans Breed

Nicholas Eberstadt's American Interest article on American demographic exceptionalism is a great antidote to the badly undermotivated worry that America has lost its animal spirits and assimilationist mojo. His conclusion:

U.S. demographic exceptionalism is not only here today; it will be here tomorrow, as well. It is by no means beyond the realm of the possible that America's demographic profile will look even more exceptional a generation hence than it does today. If the American moment passes, or U.S. power in other ways declines, it won't be because of demography.

Hell yeah! To those who worry that strong American birthrates are actually due to high rates of immigration, and that we will shortly become the Estados Unidos Norte Mexicanos, Eberstadt points out that

The single most important factor in explaining America's high fertility level these days is the birth rate of the country's Anglo majority, who still account for roughly 55 percent of U.S. births. Over the past decade and a half, the TFR [total fertility rate] for non-Hispanic white Americans averaged 1.82 births per woman per lifetime–subreplacement, but more than 20 percent higher than corresponding national levels for western Europe, and much higher if one compares “Anglo” TFRs with those of western Europe's native born populations.

So what explains the fact that America is the land where white people reproduce? Here's Eberstadt:

Public opinion surveys, for example, have thoroughly established that Americans tend to be more optimistic about the future than Europeans–a disposition that could weigh on the decision to bring children into the world. Similarly, more Americans report being “proud” of their country than do Europeans, which, quite plausibly, could lead to more births. All else equal, patriotism or nationalism may conduce to higher birth rates. Most portentously, perhaps, survey data indicate that the United States is still in the main a believing Christian country, with a high percentage of households actively worshipping on a monthly or weekly basis. In striking contrast to western Europe, which is often provocatively (but not unfairly) described as a post-Christian territory these days, religion is alive and well in the United States.

He then goes on to lament that the U.S. Census collects no data on religious affiliation. My gut says that Eberstadt wants the religiosity hypothesis to be true but seems to know that the macro-level trend in religious participation cuts the wrong way for his theory, which perhaps is what led him to produce this sentence:

Attempts to connect those two factors on the basis of broad, aggregate observations and trends run the risks of committing what statisticians call the “ecological fallacy”–mistakenly associating two unrelated phenomena for want of examining relationships at the individual level.

Well, I will run the risk by showing you a chart of the aggregate trend in religious participation in the U.S.
Religious Participation in the United States, 1972-2002
This is from Ronald Inglehart and Pippa Norris's Sacred and Secular: Religion and Politics Worldwide. The U.S. has been getting markedly less religious, even during the upsurge in fertility after the mid-70s nadir. Norris and Inglehart also note that the U.S. is not really that exceptional in religiosity relative to, say, Italy, which has about the lowest birthrates around. For the religiosity hypothesis to account for rising and then stable white fertility rates, we'd need to find that the ever-smaller proportion of white religious people have been breeding at ever-higher rates. Perhaps certain denominations have been pumping out neonates at rates sufficient to offset the general decline. But in that case, fertility wouldn't be a function of religiosity generically but of Mormonism specifically — just for example.
I like the optimism explanation. It's easy to see why folks would refrain from reproduction if they thought their kids had only a broiling, denuded planet full of wretched consumer-zombies living pointless lives in cookie-cutter McMansions and soulless big box strip malls to look forward to. The data are convincing. This Harris Poll lays it out:

Nearly two-thirds (65%) of adults in the United States say they expect their lives will improve in the next five years [Best in the world!] . . . At the other end of the spectrum, only 23 percent of Germans, 35 percent of Austrians, 36 percent of Belgians, and 37 percent of the Dutch expect their personal situations will improve.

In a fantastic paper [pdf] by Deutsche Bank Research's Stefan Bergheim, the OECD countries with higher average self-reported happiness also had higher birthrates. And what are the correlates of high levels of happiness? Bergheim says, high trust, low corruption, low unemployment, high education levels, high incomes, high employment rates for old people, small shadow economy, high levels of economic freedom, low employment protection, and, well, high birth rates. We should consider the possibility that some portion of high happiness and high birthrates are jointly caused by these other variables. Bergheim observes that in happy countries, “societal institutions and social cohesion are evidently so good that many people decide to have children.” However, social cohesion happens not to be the U.S.'s greatest strength relative to the European countries. But how about this?

Leaving France [which appears to have implemented successful natalist initiatives] aside, the overall analysis of the ten happiness-relevant dimensions in this report shows that a truly successful family policy is normally accompanied by good conditions in many other segments such as the labour market.

Now we're getting somewhere! It turns out that America's optimism outstrips even it's own considerable levels of happiness. Maybe we're just a sunny bunch, laboring under a mass delusion. Or maybe Americans expect the future to turn out well on the basis of past experience. I think flexible American labor markets have something to do with this.
In a fascinating review of recent literature in family economics by Shelly Lunberg and Robert Pollack question the effectiveness at policy aimed specifically at encouraging higher birthrates:

Kohler, Billari, and Ortega (2006) review studies of population policies in low-fertility countries, including family cash benefits and work–family reconciliation policies such as parental leave and childcare subsidies. They report that the effects of such policies are at best only modestly positive and have more influence on the timing of births than on completed family size. They conclude that policy measures tend to affect reproduction only in the long-term, so that consistent and credible application of policy over time may be a precondition to effectiveness. They also suggest that policies reducing economic uncertainty in early adulthood—for example, reducing high unemployment—may have stronger pro-natalist effects than subsidizing births or childcare. Children imply very high costs, both in money and time—particularity mother's time—over many years. Hence, governments can only influence fertility decisions with very large subsidies, or with credible long-term commitments to support childrearing. [emphasis mine]

At this point, the correct question to ask about exceptional American fertility is: what would Gary Becker say? Why not this? If white Americans produce more children than their European counterparts, then the (expected total) cost of children must be lower for Americans, especially women. Maybe this has to do with some mix of confidence in the possibility of successful re-entry into the work force after time out, or in the possibility of flexible work arrangements. Might American optimism have something to do with the fact that things really are better economically in the U.S.? It might. In any case, the belief, true or not, that things are getting better must have some effect. If we bring our children's welfare inside our own welfare functions, the expectation of an improving standard of living for our children lowers the cost of having them. Right?
It's late. That'll have to do, as a start.