Washington -- With the alarmists and neo-Malthusians in charge of the megaphones at the Cairo U.N. World Population Conference, it might be useful to remember a few facts about that terrible thing called ''the population explosion.''
It is said that population growth harms, or dilutes, economic growth. But, as it happens, the country with the greatest sustained population explosion in history is also the one that had the greatest economic explosion. It became the most powerful and influential nation in history -- while undergoing what is these days often regarded as a harmful explosive demographic experience. America's first census in 1790 recorded 3.9 million people, and its 1990 census totaled almost 250 million -- a more than 60-fold increase.
A populous country is not necessarily powerful, or super-powerful. Look at Russia, India, Indonesia and, for the moment, China. On the other hand, there will be no thinly populated superpowers. I guarantee it. Belgium? England? Forget it. Japan? It's not so small -- 125 million -- but it won't be one either, I bet, in large part because its current incredibly low birth rate will yield a diminishing population.
Since the time of Thomas Malthus two centuries ago it has been said that growing population will outrun food supply. But the opposite happened and is still happening. Since the 1950s food production has tripled while population has doubled, and food prices have been falling. (Population is now growing at 1.5 percent per year, and that rate is sinking faster than anyone recently thought possible.)
Remember, too, the real cause of the population explosion, the next time you hear how terrible it is. People are living longer, infants especially. It is one of the great achievements in human history. It then takes a while for parents to realize that so many more of their children will survive. Fertility then falls, as it is now falling. That is called ''the demographic transition.''
You will hear a lot about ''urbanization,'' related to the population explosion. But why are people moving to the cities? Rule one in human affairs is that free people behave in their own best interest. People move to the cities from rural areas because they do better in the cities. The slums of the world are poor and unsanitary, but the people who moved there voted with their feet because life was better for them than in the impoverished countryside. Moreover, moving to the cities is a sure bet to lower fertility rates, quickly.
Total Fertility Rates (the number of lifetime births per woman) have been tumbling, in both the developed and less-developed countries. In 1960-65, the global fertility rate, according to the United Nations was 5.0. The new 1994 ''World Population Data Sheet'' of the Population Reference Bureau reports a rate of 3.2, with 2.1 the number needed to assure a stable population over time. Thus, in only three decades, the world has progressed 62 percent toward the ''replacement rate.'' Among the countries whose fertility has dropped sharply are Mexico, Brazil, India, China and Egypt.
Accordingly, it is much more likely that global population will top out at 7 billion to 8 billion rather than the 10 billion to 12 billion hawked in Cairo.
And, finally, one of the biggest philosophical issues has been more or less resolved. Ten years ago at the Mexico City Population Conference the position of the Reagan-administration delegation was caricatured as ''Capitalism is the best vTC contraceptive,'' that is, modern economic development on the market model is what leads most quickly to fast economic growth, leading directly to low birth rates.
Others at the conference argued that the socialist or communist models were better, or that only more contraceptive aid to the poorer countries would do the job. Today, after the end of the Cold War, nations everywhere believe that markets are the way to go. And despite the poor-mouthing coming from Cairo, family planning is not that expensive a project, and, rest assured, it will be well-funded in the years to come.
Ben Wattenberg, a fellow at the American Enterprise Institute, is the host of the weekly public television program, ''Think Tank.''