Children are in the vanguard of America's increasing racial and ethnic diversity. The majority of newborn babies today are among racial and ethnic minority populations, according to recent Census Bureau estimates. U.S. Census Bureau projections indicate that by 2043, non-Hispanic whites will cease to be a majority of the American population. For America's children and youth, the future is now. American diversity is fueled by differing fertility rates among racial and ethnic groups, changes in the racial composition of women of childbearing age, and immigration. Here we document how unfolding demographic forces have placed today's children and youth at the forefront of America's new racial and ethnic diversity. America's rapidly changing racial and ethnic composition hasimportant implications for intergroup relations, ethnic identities, and electoral politics.