Real estate agents often say, “It’s always a good time to buy a house”—because they earn their commission whether or not it’s actually a good time to buy a house.

In the same vein, over at the Wall Street Journal it’s always a good time to increase immigration. The paper’s editorial page—notorious for repeatedly advocating a constitutional amendment saying, “There shall be open borders”—recently ran a column by Jason Riley, a member of the editorial board, entitled “Want to Raise Birthrates? Immigration Is the Key.” 

Curiously for a newspaper focused on business and economics, the column contains no numbers to back up this assertion.

Now, falling birthrates are an issue for almost all countries, developed or otherwise. The way this is usually expressed is the total fertility rate, or TFR. This represents the number of children the statistically average woman is likely to have in her lifetime. To maintain a stable population, a nation needs a TFR of slightly above two—one for mom, one for dad, and an additional fraction to account for child mortality.

Every nation except Israel in the Organization for Economic Co-operation and Development (OECD) has below-replacement TFR, and fertility has been dropping almost everywhere. Even countries such as Mexico, Brazil, Iran, and Turkey have below-replacement fertility, and many other developing countries will soon join them.

A TFR below 2.1 will eventually lead to a declining population. In itself, a smaller population doesn’t have to be a problem, since countries had fewer people in the past and got along fine. The real problem comes from the increasing share of the elderly, leading to fears of national senescence. In South Korea, perhaps the most extreme example of a birth dearth, those aged 65 and over are projected to climb from about 20% of the total population today to nearly half in 50 years.

It is in this context that the Journal published its number-free column on immigration as a way to boost fertility. Luckily, colleagues of mine at the Center for Immigration Studies crunched the numbers—and it turns out immigration does little, if anything, to increase the overall fertility rate, at least in the United States.

Using Census Bureau data from 2023, Steven Camarota and Karen Zeigler found that immigration raises the nation’s overall TFR by a minuscule 0.08, to 1.8 children per woman, from 1.73 for the U.S.-born alone. So the presence of 50-plus million immigrants increases America’s fertility rate by just eight one-hundredths of a baby. This is because while immigrants do in fact have slightly higher fertility than the native-born, it’s not all that much higher, and the existing population is so large that the current rate of new immigration of roughly one million per year would have to be increased by orders of magnitude to have any significant impact.

And looking below the topline number reveals interesting trends. Riley’s Journal column asserted that “What has helped prevent U.S. birthrates from going off the deep end is the presence of Hispanics, who tend to have more children.” Again, no numbers. It turns out that when you break down the U.S.-born by ethnicity, the TFR for Hispanics is only six one-hundredths of a baby higher than for whites—hardly enough to make much of a difference.

What’s more, the fertility rate for immigrants has fallen more since 2008 than the rate for the native-born, pointing to a convergence in fertility rates.

All this assumes a static picture—immigrants are simply added to the calculation of fertility rates, and that’s it.

In fact, evidence strongly suggests that immigration actually reduces fertility among the native-born. My colleagues found that the higher the share of immigrants in the largest metro areas, the fewer births per thousand (a simpler measure of fertility). Earlier research suggests a number of reasons for this, from increased housing costs, especially for the less well-off, to increased diversity, which may make it harder to find a suitable partner.

Another colleague, Jason Richwine, estimates that the reduction in fertility among the native-born caused by immigration may entirely cancel out the effect of immigrants’ slightly higher fertility on the overall national rate. So, from a fertility perspective, it’s a wash.

In his Journal column, Riley rightly observes futile attempts in other countries to goose fertility: “Trying to bribe women into having more children than they want has been largely unsuccessful.” Unfortunately for Riley, attempting to raise our nation’s fertility rate via immigration is no more successful.

This doesn’t mean that nothing can increase fertility. Maybe there is some combination of financial incentives that will work. Or maybe repealing car seat mandates could help. Or it might require a revival of religious sentiment, though government policies are unlikely to play a role there.

But one thing is for sure: as Iowa congressman Steve King tweeted in 2017, “We can’t restore our civilization with somebody else’s babies.” We’ll have to do it ourselves.