Most of the rich, developed countries in the world are facing an aging crisis, as their fertility rates fall to unprecedented lows. But analysts say the United States is better equipped to deal with the challenges of aging than almost any other developed country--thanks to its relatively high birth rates and immigration.
Jolene Ivey has always dreamed of having a large family.
"Aaron, your big piece is ready to go, come over here and help David," says Jolene Ivey.
Now, Ms. Ivey is living her childhood dream. She and her husband Glenn live in suburban Maryland with their five sons aged five to 15.
"I did it all by myself!" says one of the boys.
"Well, I just have one brother and it seemed like it would be fun to have a big family, and I read those books, you know, 'cheaper by the dozen' kind of thing. And it just seemed like fun to have a lot of siblings," says Ms. Ivey.
American families like the Ivey’s are helping to drive U.S. fertility levels higher than those of almost every other developed country. The United Nations Population Division says that all around the world, fertility levels have fallen sharply since the 1970s. But the United States is almost unique among developed countries in defying this demographic trend.
Bill Frey is a demographer at the Brookings Institution research group in Washington D.C. Mr. Frey says that the United States is the only large, developed country with a growing population.
"The population of the U.S. is going to grow probably by another 100 million people over the next 50 years. And the major reason for that is the higher fertility rate than is the case in a lot of other developed countries," says Mr. Frey.
The United Nations says that Americans have maintained their birth rate at an average of just above two children per woman, about the level needed to keep the population stable.
In the 1970s, American birth rates dipped as women began to enter the work force in larger numbers.
In the late 1980s, however, American fertility began to rise again, just as European fertility kept declining to new lows.
Mr. Frey says the American dream of having two or more children may have been sustained by the steady growth of suburban housing outside urban areas. In 2000, more than half of Americans lived in the suburbs, where Mr. Frey says the infrastructure is most supportive of family life.
"Not all of them have families, not all of them are capable of having families. But if you don't have a family, and you don't have children, there's something in the back of your head I think for a lot of people that makes you feel a little bit left out in the United States," says Bill Frey.
Mr. Frey says another reason for American population growth is immigration. The United States accepted some 11 million legal immigrants in the 1990s and immigration rates are expected to stay high. Immigrants to the United States also have higher birth rates than the native-born population.
Richard Jackson, head of the global aging initiative at the Center for Strategic and International Studies, CSIS, in Washington D.C., says the United States will grow younger relative to Europe and Japan over the next few decades.
"America is actually well positioned to confront the age wave. It has the youngest population in the developed world. And thanks to our higher rate of fertility and our substantial rate of net immigration, we'll have the youngest population by an even wider margin 20 or 30 years from now," says Mr. Jackson.
Still, some argue that the United States cannot afford to be optimistic about its demographic future. Phil Longman is a demographer at the New America Foundation research group in Washington D.C.
"The great vulnerability of the U.S. is its cost of health care, which is so much dramatically higher than literally anywhere else in the world. Without any commensurate improvements in public health, Americans live shorter lives with greater disabilities than people who live in countries that spend half as much on health care," says Mr. Longman.
As Americans plan for their future, parents like Jolene Ivey are counting on their children to support each other.
"When my husband and I get old and frail and feeble-minded, they'll have each other to call and go 'do you know what mom said?' you know and that'll be good for them," says Ms. Ivey.
It will also be good for the future of the United States, which most demographers say will be in a healthier position than almost all of its developed country neighbors.