In the next 35 years, America's minority population will be the majority, but among the young, "majority-minority" populations already blanket many places.

Minority youth under age 20 outnumber white youth in 504 U.S. counties -- almost one in six, according to research by Cornell demographer and sociologist Daniel Lichter, professor of policy analysis and management in Cornell's College of Human Ecology, and Kenneth Johnson, a demographer at the University of New Hampshire's Carsey Institute.

Their research is published in the March (Vol. 36:1) issue of Population and Development Review.

Already, more than 47 percent of all children under age 5 are minorities. Of all young people, 43 percent were minorities in 2008 (compared with 31 percent of those 20 or older), up from 38.5 percent just eight years earlier.

The U.S. Census Bureau recently projected that racial and ethnic minorities -- everyone but non-Hispanic single-race whites -- will be the majority population by 2042, Lichter said, and will constitute 54 percent of the U.S. population by 2050.

But "in many parts of America, the future is now," Lichter said.

Lichter noted that "two powerful demographic forces" are behind the changing population trends "and place young people in the vanguard of America's new diversity."

The first, according to the research paper, is that "America's changing racial and ethnic composition has been fueled by extraordinary growth of fertility rates of the Hispanic population in recent years." Although Hispanics represent only 15 percent of the U.S. population, they accounted for more than half of all U.S. population growth between 2000 and 2007. The second is that the absolute number of non-Hispanic white young people has been declining.

The analysis of 2000 to 2008 Census data on the growing diversity among America's youth "demonstrates that fertility -- and the growth of the population of children and youth -- is the driving demographic force underlying America's growing diversity and multiculturalism," said Lichter, who also serves as the director of Cornell's Bronfenbrenner Life Course Center.

The rapidly growing racial diversity among America's children has heightened the need for such public policy responses as culturally sensitive obstetrics and pediatric care, pre-school and English as a second language programs, more recreational programs, teen employment and juvenile justice.

However, the researchers write: "The frequent claim that we live in an increasingly multiracial or multicultural society -- a fact that is both celebrated and feared -- does not necessarily mean that these national patterns are played out [everywhere]." Indeed, they add that America's majority and minority populations' exposure to each other has been slow, "despite unusually rapid shifts in America's racial mix over the post-2000 period."

Although many "broad geographic swatches of America nevertheless remain mono-racial, where few minorities live," conclude the researchers, "growing racial and ethnic diversity among children and youth is a harbinger of demographic things to come in America."

The research was funded by grants to the Carsey Institute from the Annie E. Casey, W.K. Kellogg and Ford Foundations.