On the 2010 Census, President Barack Obama, identified himself as  “black.” But millions of Americans consider themselves “bi- or multi-racial.”  And their numbers are rising.

The number of mixed or multi-racial people in the U.S. rose by 6.6 percent between 2010 and 2012. This number is growing faster than any other racial group.

There are two reasons. More people are marrying across racial lines and more multi-racial children are being born....