WASHINGTON — For the first time, racial and ethnic minorities make up more than half the children born in the U.S., capping decades of heady immigration growth that is now slowing.

New 2011 census estimates highlight sweeping changes in the nation’s racial makeup and the prolonged impact of a weak economy, which is now resulting in fewer Hispanics entering the U.S.

“This is an important landmark,” said Roderick Harrison, a former chief of racial statistics at the Census Bureau who is now a sociologist at Howard University. “This generation is growing up much more accustomed to diversity than its elders.”

The report comes as the Supreme Court prepares to rule on the legality of Arizona’s strict immigration law, with many states weighing similar get-tough measures.

“We remain in a dangerous period where those appealing to anti-immigration elements are fueling a divisiveness and hostility that might take decades to overcome,” Harrison said.