We Need to Know More Than Half of the Story About Falling Birthrates

Readers of my posts may remember that in May 2024, Scientific American published a story about China's demographic future that I co-authored with a Chinese PhD candidate in the Office of Population Research at Princeton University. Her name is Xueqing Wang.

Our success with this project led us a year ago to consider a new project that would compare and contrast the demographic challenges of China and India for the rest of

this century. Each of these countries now has a population of around 1.4 billion and together they account for about one-third of the human population on Planet Earth. One major difference is that China's population started shrinking in 2022 and India's population is still growing.

To proceed with this new project we needed to find an Indian demographer interested in working with us. We have been extremely fortunate in having Dr. K.S. James join us in this project. There is some serendipity involved here. I earned my B.A. from Princeton University (in 1963), Xueqing Wang earned her PhD from Princeton University (in 2025), and Dr. K.S. James joined the Center for Health and Wellbeing at Princeton University in January 2026.

Without my active collaboration with these two experts, I would not have been able to produce a Letter to the Editor worth publishing by the NY Times on any policy issue in the area of demographics.

We are now working on three separate pieces that compare and contrast specific demographic challenges for China and India. We hope to find good outlets for them within the next year.

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Falling Birthrates and America’s Future

July 16, 2026

To the Editor:

Re “The Population Forecasts Aren’t Grim Enough,” by Lyman Stone (Opinion guest essay, July 13):

Dr. Stone is correct in describing the trend in the United States and the rest of the world of rapidly falling fertility rates.

But a key point he misses is that rising productivity can more than offset a shrinking labor force. Furthermore, rising productivity is associated with rising incomes, while adding workers without any increase in productivity does not make the average worker better off.

My biggest problem with Dr. Stone’s essay is that he does not discuss the benefits of having a smaller population, which is one of the best ways of mitigating the misery expected by climate scientists as the world gets hotter and more polluted and there is further loss of biodiversity.

Finally, Dr. Stone forecasts a future of net-zero immigration for the United States and treats it as a fact instead of a policy choice. What is missing in his discussion is a view of the optimum population size for the United States. Some notion of this number is necessary to have a sensible immigration policy.

Let’s not underestimate the capacity of the human race to adapt to changing circumstances. We have adapted brilliantly to the near quadrupling of the global population in the past 80 years. It is possible to adapt just as well over the next 80 years to create a world where fertility returns to the 2.1 replacement level and the global population stabilizes at 10 billion or eight billion or some lower number, with no loss in prosperity because of increasing productivity.

Lex Rieffel

Washington

The writer was a Treasury Department economist and Brookings Institution scholar.

To the Editor:

Lyman Stone argues that population decline threatens economic vitality. History suggests a more complicated reality.

In the 19th century, New England was replete with small farms. As agriculture shifted westward, rural communities lost population as thousands of farms were abandoned. Yet New England did not collapse. As farming declined, the region’s economy shifted toward manufacturing, commerce, education and other pursuits, while abandoned farmland gradually returned to forest.

Demographic change creates challenges. But having fewer people does not automatically mean less prosperity or a weaker society. The crucial questions are productivity, technological progress and our ability to adapt while ensuring that transitions consider human needs.

Demographic decline can be followed not by collapse but by renewal.

John Seager

Washington

he writer is the president of Population Connection.

To the Editor:

Lyman Stone’s guest essay equated birthrate with population growth. The piece harked back to 1775, when land was abundant and cheap. Family farming was the primary vocation and made having large families common sense. Population grew.

Immigration was also a major reason for America’s population growth. Doing a better job of accommodating migrants, refugees and asylum seekers would also be a way of increasing America’s population without increasing the birthrate.

I found fault with the idea that more workers paying into the Social Security system was necessary in order to support retired benefit recipients. It’s income that supports the Social Security system. There is a huge amount of income in the United States that is not subject to Social Security taxes. It should be.

Dave Gallagher

Tucson, Ariz.

To the Editor:

It is the growing of the population for the sake of growing the economy that is leading us to environmental apocalypse. We have so clearly overshot already, with 8.3 billion people, that other species are going extinct at an alarming rate.

We live on a planet of finite resources. To maintain the lifestyle that we lead in the United States, we think we deserve more of those resources than anyone else. And if another country has resources we think we need, we think it’s our right to go in and confiscate those resources. This is the cause of conflict as we compete with other countries, and the extraction of those resources is doing more and more environmental damage.

In the United States, we see a cultural war, as the wealthy demand many more of those resources, which causes supply to go down and prices to go up, hurting the poor. We cannot live on this planet sustainably if we increase our birthrate. Or we might be able to, but only if we (especially the wealthy) start consuming a lot less, which would affect the economy negatively.

Katherine Schwarz

Nyack, N.Y.

To the Editor:

As someone who came to California when its population was 22 million, I don’t think it is better now with 40 million, and I doubt that an additional 10 million would improve things.

While a stable population would cause some issues with benefit programs and business plans based on population growth, it would help solve many issues that some are concerned are already at a crisis level — climate change, housing, water, food, energy, congestion, overfishing, waste disposal, general pollution and probably some others as well.

The world would not necessarily be a better place with two people in every line where there is one today.

Craig C. Taylor

Palo Alto, Calif.

To the Editor:

If we are serious about the future of our country, we must make having, raising and educating children a significant priority. Perhaps if our leaders invested in free child care, parents could work full-time jobs that provide for the necessities of a good life. And if we provided public school educators with the preparation, resources, salaries and respect they deserved, it’s possible that the best and the brightest would prepare our children for a fulfilling existence.

Until we change our priorities, the future is hardly promising.

Alexis Gerard Finger

Bala Cynwyd, Pa.

To the Editor:

Lyman Stone’s bizarre narrative treats other people’s wombs as instruments of fiscal policy. No one owes the state a child.

There are policy tools that can deal with the birthrate issue. None of them require telling people they’ve failed the nation if they don’t have more children.

Daryl Muenchau

San Diego