William H. Frey of the Brookings Institution analyzed Census figures, The Washington Post reported. He said that in 2009, the year before the 2010 Census, more than 7 percent of newborns had parents of different races, while the number of children who have one white parent and the other black or Asian doubled.
Frey said there appear to be two trends at work. One is that there are more mixed-race couples, and the other that a mixed-race identity is more acceptable.
"I think people are more comfortable in identifying themselves, and their children, as mixed race," he said. "It's much more socially acceptable, more mainstream, to say, 'That's what we want to identify them as.'"
Frey said older people with one black parent tend to identify as black -- citing President Barack Obama as an example.
Notable deaths of 2014 [PHOTOS]