WASHINGTON — Children now make up less of America's population than ever before, even with a boost from immigrant families.
And when this generation grows up, it will become a shrinking workforce that will have to support the nation's expanding elderly population — even as the government strains to cut spending for health care, pensions and much else.
The latest 2010 census data show that children of immigrants make up one in four people under 18 and are now the fastest-growing segment of the nation's youth, an indication that both legal and illegal immigrants as well as minority births are lifting the nation's population.
Currently, the share of children in the U.S. is 24 percent, falling below the previous low of 26 percent of 1990. The share is projected to slip further, to 23 percent by 2050, even as the percentage of people 65 and older is expected to jump from 13 percent today to roughly 20 percent by 2050 due to the aging of baby boomers and beyond.
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In 1900, the share of children reached as high as 40 percent, compared with a much smaller 4 percent share for seniors 65 and older. The percentage of children in subsequent decades held above 30 percent until 1980, when it fell to 28 percent amid declining birth rates, mostly among whites.
"There are important implications for the future of the U.S. because the increasing costs of providing for an older population may reduce the public resources that go to children," said William O'Hare, a senior consultant with the Baltimore-based Annie E. Casey Foundation, a children's advocacy group.
Pointing to signs that many children are already struggling, O'Hare added: "These raise urgent questions about whether today's children will have the resources they need to help care for America's growing elderly population."
The numbers are largely based on an analysis by the Population Reference Bureau, a nonprofit research group in Washington that studies global and U.S. trends. In some cases, the data were supplemented with additional census projections on U.S. growth from 2010-2050 as well as figures compiled by the Annie E. Casey Foundation's Kids Count project.
Nationwide, the number of children has grown by 1.9 million, or 2.6 percent, since 2000. That represents a drop-off from the previous decade, when even higher rates of immigration by Latinos — who are more likely than some other ethnic groups to have large families — helped increase the number of children by 8.7 million, or 13.7 percent.
The slowing population growth in the U.S. mirrors to a lesser extent the situation in other developed nations, including Russia, Japan and France, which are seeing reduced growth or population losses due to declining birth rates and limited immigration. The combined population of more-developed countries other than the U.S. is projected to decline beginning in 2016, raising the prospect of prolonged budget crises as the number of working-age citizens diminish, pension costs rise and tax revenues fall.
Depending on future rates of immigration, the U.S. population is estimated to continue growing through at least 2050. In a hypothetical situation in which all immigration — both legal and illegal — immediately stopped, the U.S. could lose population beginning in 2048, according to the latest census projections.