“Our world is overpopulated.” If you repeat something often enough, it es “truth”. In 1968, Paul Ehrlich wrote The Population Bomb, warning that we’d all soon be fighting over food, space, and power as the earth sagged under the weight of all those darned people.

He was wrong, of course, and not just wrong: spectacularly wrong. It didn’t keep him from being a celebrity or from his ridiculous notion from being believed. But he was still wrong.

In What to Expect When No One’s Expecting: America’s Coming Demographic Disaster, author Jonathan V. Last attempts to point out the fallacies of Ehrlich and his ilk. Last is clear: our world is not overpopulated; we are vastly under-populated, and it’s a problem. He goes so far as to say that America has a self-imposed “One-Child Policy” that is leading us to demographic disaster.

Last is chiefly concerned with the problems under-population will cause America, but he uses several other countries to illustrate where we are headed. There are a lot of numbers in this book: financial figures about the costs of raising children, population numbers, fertility rates, the changing age of marriage. The conclusion doesn’t get lost in all the numbers: we don’t have the ability – population-wise – to take care of ourselves. That is, with programs like Social Security and Medicaid requiring a vast army of workers to keep them propped up and paying out, we can’t keep up. And if there aren’t enough workers to pay into these systems, there certainly aren’t enough people to take care of Grandma and Grandpa as they age and need more and more care.

There are a number of nations far ahead of America in this population pitfall. Last uses Japan, Iran, Russia, and China (among others) to let us know what to expect – so to speak. Japan, for instance, has been in a population free-fall for years. Babies are so rare in Japan, Last says, that the nation sells more adult diapers than baby diapers. The Japanese government has tried mightily to bolster baby-making: creating allowances for families that have kids, generous child and family care leave policies for workers, expanded after-school programs. It may be too little, too late for Japan.

What are Last’s conclusions for America? First, once a nation hits a certain demographic tipping point, there’s almost no way back. You aren’t trying to change the course of a car, but of a battleship. Second, government tinkering and social engineering (such as Japan’s baby-making incentives) don’t work: you can’t force people into having children. (By the way, it’s this type of social engineering that got us into trouble in the first place. As it turns out, it is a lot easier to get people to stop having kids than to have them.) If people are going to have children, there must be a culture in place that values marriage, children, and religious values (sorry, atheists, but it’s true.) Specifically, Last says America must allow adults to keep more of their wages, increase tax relief for having more children, and reduce the economic distortion that Social Security currently creates.

Last doesn’t paint a pretty picture; after all, he uses the word “disaster” in his title. Not everyone is going to wade through all the charts, numbers and figures of Last’s book, but it will do well for us to pay heed to the message: America, we need more people. People who can work, create, pro-create, educate, learn, and carry us into the next few centuries. We must burgeon or we will break.