As the debate over illegal immigration from Mexico rages in Washington and across the country, and as the administration’s reform bill hangs by a thread, few Americans are aware that this problem is on track to decline, and will eventually become a vague memory.

There has been a stunning decline in the fertility rate in Mexico, which means that, in a few years, there will not be nearly as many teenagers in Mexico looking for work in the United States or anywhere else. If this trend in the fertility rate continues, Mexico will resemble Japan and Italy—rapidly aging populations with too few young workers to support the economy.

According to the World Bank’s 2007 Annual Development Indicators, in 1990 Mexico had a total lifetime fertility rate of 3.3 children per female, but by 2005, that number had fallen by 36 percent to 2.1, which is the “break even” point for population stability in developed nations. The large number of women currently in their reproductive years means that there are still quite a few babies, but as this group ages, the number of infants will decline sharply. If this trend toward fewer children continues, there being no apparent reason for it to cease, the number of young people in the Mexican population will decline significantly just when the number of elderly is rising. As labor markets in Mexico tighten and wage rates rise, far fewer Mexican youngsters will be interested in coming to the United States. Since our baby boomers will be retiring at the same time, we could face a severe labor shortage.

Some politicians fear that we are being “Mexicanized.” In fact the opposite may be underway.

There have been significant declines in fertility rates across Latin America, but Mexico’s has been unusually sharp. In El Salvador, another source of U.S. immigrants, the rate declined from 3.7 in 1990 to 2.5 by 2005. Guatemala is now at 4.3, but that is far lower than it was in 1990. Jamaica, another source of U.S. immigrants, has fallen from 2.9 to 2.4 over the same period. Chile and Costa Rica, at 2.0, are actually slightly below a replacement rate. Trinidad and Tobago, at 1.6, is well below ZPG. For all of Latin American and the Caribbean, a rate of 3.2 in 1990 fell to 2.4 in 2005, a decline of 25 percent. This means less pressure on the United States from illegal immigrants from the entire area, not just from Mexico. A powerful demographic transition is well underway, and soon many of these countries may be worried about there being too few babies rather than too many. We may miss this labor, and wonder how we will replace it.

What has changed? Better education and improved job opportunities for women mean that it has become quite expensive for them to leave the labor force to have more children. The improved availability of birth control technology and liberalization of abortion rules in some countries mean that it is easier for women to avoid that outcome.

Another reason for the particularly sharp decline in Mexico is the cultural influence of the United States. Some politicians fear that we are being “Mexicanized.” In fact the opposite may be underway. NAFTA, our mass media, the more widespread use of English, and the large number of people going back and forth (legally or otherwise) mean that Mexicans are increasingly influenced by our culture, and that implies fewer babies, The United States also has a fertility rate of 2.1, but that is the same as it was in 1990. Mexico is becoming more similar to the United States, which must frustrate their nationalists.

The main point for the United States is that we have only a temporary problem with illegal immigration from Mexico. For another decade or a bit more we must attempt to limit such entry, but then the problem will fade like the smile on the Cheshire Cat. Lou Dobbs, Rep. Tancredo and their nationalistic friends can calm down and relax.

Robert M. Dunn, Jr. is a Professor of Economics at the George Washington University.

Image credit: Photo by Flickr user pies cansados