Among the roughly 4 million children born in the United States between July 2010 and June 2011, 50.4 percent were Hispanic, black, Asian-American or in other minority groups -- up from 48.6 percent in the same period two years earlier and 49.5 percent when the decennial census was taken in April 2010, the bureau said.
In the July-to-June stretch, non-Hispanic white children accounted for less than half the country's births. It's the first time that has ever happened.
Minorities still make up about 37 percent of the overall U.S. population, the bureau said, but they are a majority of the population in California, Hawaii, New Mexico, Texas and the District of Columbia.
Non-Hispanic whites will be outnumbered in the United States by 2042, the bureau projected.
Social scientists said the new status of newborns forming America's first "majority minority" generation is a harbinger of change.
"This is a watershed moment," Johns Hopkins University sociologist Andrew Cherlin told The Washington Post. "It shows us how multicultural we've become."
The shift is attributed in large part to an aging non-Hispanic white population, analysts said.
The median age for non-Hispanic whites is over 42, so many are beyond their prime childbearing years.
By contrast, the median age for Hispanics is under 28. Blacks and Asians have median ages in their early 30s.
Among non-Hispanic whites, births now barely exceed deaths, analysts said.
Last year 1,025 non-Hispanic whites were born for every 1,000 who died, compared with a ratio of 3,940 births to 1,000 deaths for all other ethnic groups, University of New Hampshire senior demographer Kenneth Johnson told The Wall Street Journal.
Data for 2010 show Hispanic women give birth to 2.4 babies on average, compared with 1.8 babies for non-Hispanic whites, the Pew Hispanic Center said.
African-Americans are the largest minority among adults over 50, but for anyone younger, Hispanics are the second-largest population group, after whites of European descent, Brookings Institution demographer William H. Frey told the Journal.
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