The Hague, Netherlands -- While a lineup of delegates, including pro-abortion first lady Hillary Clinton, spoke in the Netherlands this week on ways to reduce world population, American social policy experts point out fertility rates are already falling here and in dozens of other modern nations.

"The population issue of the 21st century is not going to be overpopulation, but depopulation," says Allan Carlson, president of the Howard Center for Family, Religion and Society in Rockford, Ill.

Mr. Carlson and others who worry about shrinking populations think modern prosperity helps stifle fertility in a country where only 11 states, led by Utah, had fertility rates of more than 2.1 children per woman. They say couples who have disposable incomes, higher education, and a wife in the work force have interests that mcompete with raising children.

And, demographically speaking, "pregnancies delayed -- to some extent -- are pregnancies denied," American Enterprise Institute scholar Ben Wattenberg wrote in his book on depopulation, "The Birth Dearth."

In the United States, where 28 years of subpar fertility rates have been offset by an influx of young immigrants, social policy experts worry about the long-term consequences of pro-abortion policies.

They say family growth -- especially among married couples --could be stimulated with tax policies that favor families who are raising children.

The country could also use a new national attitude that says children are valuable to society and large families should be celebrated, Mr. Carlson says. Workplace changes are also key, says Danielle Crittenden, author of "What Our Mothers Didn't Tell Us: Why Happiness Eludes the Modern Woman."

Getting momentum for cultural reforms to increase fertility won't be easy, however, while people are still arguing over whether overpopulation or depopulation is the main problem.

In The Hague this week, hundreds of delegates at The Hague forum on population and development are discussing how far the world has come since the 1994 population conference in Cairo, where many pro-abortion goals were set. A second major meeting on the issue is set for next month in New York.

Fertility rates, which track women's childbearing over their lifetimes, are key indicators of population. To replace itself, a population needs each woman to have an average of 2.1 children over her lifetime to replace herself and her mate, excluding immigration.

Those who worry about overpopulation note that two-thirds of the world's nations have "replacement-level" or higher fertility rates. But those who worry about depopulation note that 58 of the world's countries have less-than-replacement fertility rates.

Five of these countries -- Bulgaria, Italy, the Czech Republic, Romania and Spain -- have a rate of 1.2 children per woman, and other countries, such as Japan, are only slightly higher.

In the United States, only 11 states have replacement-level populations, according to the National Center on Health Statistics. The rest have below-replacement fertility rates.