Some of the increase is explained by immigration. Hispanics have the highest fertility rate — about 2.9 — followed by blacks (2.1), Asians (1.9) and whites (1.86). But Hispanics do not represent enough of the population to fully explain the trend, and the fertility rate of U.S. whites is still higher than that of other developed countries.
For the first time in 35 years, the U.S. fertility rate has climbed high enough to sustain a stable population, solidifying the nation’s unique status among industrialized countries.
The overall fertility rate increased 2 percent between 2005 and 2006, nudging the average number of babies being born to each woman to 2.1, according to the latest federal statistics. That marks the first time since 1971 that the rate has reached a crucial benchmark of population growth: the ability of each generation to replace itself.
“It’s been quite a long time since we’ve had a rate this high,” said Stephanie J. Ventura of the National Center for Health Statistics. “It’s a milestone.”
While the rising fertility rate was unwelcome news to some environmentalists, the “replacement rate” is generally considered desirable by demographers and sociologists because it means a country is producing enough young people to replace and support aging workers without population growth being so high it taxes national resources.
“This is a noteworthy event,” said John Bongaarts of the Population Council, a New York-based think tank. “This is a sign of demographic health. Many countries would like to be at this level.”
Europe, Japan and other industrialized countries have long had fertility rates far below the replacement level, creating the prospect of labor shortages and loss of cultural identity as the proportion of native-born residents shrinks in relation to immigrant populations. In contrast, many developing nations’ birthrates far exceed the replacement rate, fueling poverty and social unrest.
“Over the long term you can’t have significant continued growth or continued decline,” said S. Philip Morgan, a Duke University sociologist. “Neither one is sustainable.”
The reasons for the unusual U.S. fertility rate are the focus of intense interest. Experts can only speculate, but they cite a complex mix of factors, including lower levels of birth control use than in other developed countries, widely held religious values that encourage childbearing, social conditions that make it easier for women to work and have families, and a growing Hispanic population.