In a new report, economists writing for the Brookings Institution estimate that the United States could see “on the order of 300,000 to 500,000 fewer births next year” as a result of the economic recession triggered by the novel coronavirus.

The economists, Melissa S. Kearney and Phillip Levine, derive their estimates from data on birthrates during the Great Recession and the 1918 flu pandemic. Both of those upheavals had a considerable negative impact on fertility.

During the Great Recession, for instance, states that experienced steeper job losses tended to see more dramatic reductions in their birthrates between 2008 and 2011. Looking at the country as a whole, they found that “in 2007, the birth rate was 69.1 births per 1,000 women ages 15 to 44; in 2012, the rate was 63.0 births per 1,000 women.” That works out to a 9 percent drop, or roughly 400,000 fewer births.

The reason? Children are expensive, and having a child is in many ways a financial decision. The loss of a job or otherwise uncertain prospects for a steady income lead many would-be parents to postpone having kids until things are more settled. In economic jargon, birthrates are “procyclical” — they tend to rise during times of economic growth and fall during recessions.

Birthrates also track pandemics, as the fertility data from the time of the 1918 pandemic shows above. The chart shows a striking correlation: For each wave of the pandemic, birthrates dropped sharply nine months after deaths peaked.

Crucially, in the wake of the 1918 pandemic, American mothers didn’t “make up” for the previous decline in fertility by having more kids. Rather, the pandemic left a permanent mark on American families, with many having fewer children than they would have otherwise, leaving tens of thousands of future American citizens permanently unborn.

What does all that mean for the current crisis, which involves not just a pandemic or an economic collapse, but both simultaneously? Using the skyrocketing unemployment rate as a baseline and factoring in the additional effect of an ongoing public health crisis with no end in sight, Kearney and Levine estimate we’re in for a decline of anywhere from 300,000 to 500,000 births.

And that’s something of a best-case scenario. If the pandemic lingers or the unemployment rate stays depressed through next year, effects on birthrates are likely to be even larger.

“The circumstances in which we now find ourselves are likely to be long-lasting and will lead to a permanent loss of income for many people,” Kearney and Levine write. By one estimate, for instance, over 40 percent of jobs lost during the pandemic may never come back.

It’s difficult to overstate the impact of such a loss on American society — particularly coming just 10 years after the fertility bust caused by the Great Recession.

“We expect that many of these births will not just be delayed — but will never happen,” Kearney and Levine write.

Economists use a tool called the value of a statistical life, or VSL, to help put losses of life on a level playing field with other policy considerations. Using a standard VSL of roughly $10 million, the permanent loss of half a million births works out to an economic loss of about $5 trillion over the coming decades.

Of course, at the individual level, the fertility cost is literally incalculable. How does a parent put a price tag on a child that was never had? What is the loss to an only child who will never have siblings to play with?

The discussion is a reminder that even after the pandemic is behind us, it is likely to leave a deep scar on society for years to come.