Change in Federal Form Makes 'Multiracial' Fastest Growing Group

"By knowing who is multiracial, we will enlarge these donor pools and save more people," says Project RACE's Graham. "This is a very ¬critical issue."

"Information is needed to allocate resources and do society's business, so having accurate information is simply consistent with what benefits everyone," adds Mr. Portantino.

About 42 percent of those who have checked more than one race on US census forms are under age 18. And it is the young, polls and studies show, who are most open to embracing multiracialism and the multiracial label.

"The least inclusive generation is the one today that is 65 and older, and the most inclusive are those under 30," says Leonard Steinhorn, professor at American University's School of Communication and author of two books on race and social change.

"These are fundamentally different worldviews. One is moving offstage and the other is moving onstage, and these new demographic figures reflect that."

Social scientists point to an array of other reasons for the shift-ing view of multiracialism -- from cultural change and social progress since the civil rights era to the aging of the baby boomers to, even, the rise of hip-hop.

"Jazz was unable to do it, nor could blues or rock and roll, but hip-hop came along and now we have Eminem and Asher [Roth] -- both white men who have released excellent rap albums in the same year," says James Peterson, assistant professor of English and African Studies at Bucknell University.

And more and more famous people are multiracial, including actors such as Keanu Reeves and Cameron Diaz, Mr. Peterson and others point out.

The two most famous multiracial people -- President Obama and Tiger Woods -- are frequently in the headlines.

In a lighter moment last year, Mr. Obama -- whose father is Kenyan and whose mother is a white American -- surprised reporters by referring to himself as a "mutt."

And in 1997, golfer Tiger Woods startled many Americans when he objected to being called African-American, and instead referred to himself as "Cablinasian," to reflect his blend of Caucasian, black, Indian, and Thai blood.