WASHINGTON (Reuters) - For the first time, there are more black, Hispanic and other minority babies being born in the United States than white babies, according to government data released on Thursday that confirm a long-growing trend. Among children younger than age 5, 49.7 percent were a minority or mixed race last year, up from 49.0 percent in 2010, according to the agency, which tracks the U.S. population. The figures are also likely to reignite debate over what it means to be an American in an election year where race, poverty and immigration are emotional campaign issues. The 197.5 million whites of all ages in the United States still make up nearly two-thirds of the nation, the Census Bureau said. Its data show 36.6 percent of the U.S. population were minorities in 2011 compared to 36.1 percent in 2010. The growing Hispanic population and related immigration concerns, particularly in southern states that border Mexico, are major issues in November's presidential and congressional elections. Republicans have taken a tough stance against illegal immigration and vowed to cut spending for social programs that largely impact minority groups. Democrats have said they back broad immigration reform that could, for example, allow children who are illegal immigrants but have grown up in the United States to have a pathway to citizenship. Vanessa Cardenas director of a diversity project at the nonprofit think tank Center for American Progress, said despite some conservatives' resistance to the nation's changing racial make-up, the numbers make clear that the United States is increasingly diverse. That means that citizens and policy makers will need to rethink spending priorities and other issues, said Cardenas, who was born in Brooklyn to parents from Bolivia. The communities that are growing the most are facing the biggest challenges in terms of education and the wealth gap. If we don't do what we can to make sure these kids succeed ... if we as a country want to be better, we have to invest in these kids," she said. Her project, called Progress 2050, is aimed at policies amid growing racial and ethnic diversity. Political economist Nicholas Eberstadt, an American Enterprise Institute scholar, said that the findings did not foreshadow anything in a "fluid society" with a historic pattern of assimilation that has worked well. "I don't think this notional milestone is portentous for the future," Eberstadt said. The Census Bureau findings also show: Asians were the second-fastest growing population, rising 3 percent to 18 million. More than half of all residents in Hawaii, California, New Mexico, Texas and Washington, D.C., were minorities as of last year. Reporting By Susan Heavey; Editing by Xavier Briand