The daughter of a Jamaican father and Indian mother, both immigrants, Kamala Harris reflects the United States' changing demographics.

When she steps onto the stage Thursday evening in Chicago to accept the Democratic Party's nomination as their presidential candidate, she will represent the country's fastest growing racial category.

Some 42 million Americans now identify as multiracial, or 13% of the country, according to the U.S. Census Bureau. That is up from 2% in 2000 when the census first allowed people to select multiple races.

America has long been a self-styled "melting pot" of people who trace their origins around the world, but in practice some states legally segregated citizens by race until the civil rights laws of the 1960s and laws prohibiting interracial marriage were not overturned until 1967.

Social change since, though, has been rapid. Barack Obama was elected as the country's first Black president in 2008, and Harris would be the first Black woman and South Asian if elected in November.

"We're living in a situation 50 years later where we could be looking at our second mixed-race president, and it's beautiful," said Svante Myrick, president of People for the American Way, an advocacy group, whose father was Black and his mother white.

America's future will look even more diverse. The vast majority of multiracial people are younger than 44 and a third are still children.

The trend has been met by confusion, upset and worse from some of the U.S.'s shrinking white majority. Republican presidential candidate Donald Trump drew groans at a gathering of Black journalists last month when he falsely portrayed Harris as pivoting from Indian to Black.

"I don't know, is she Indian or is she Black," Trump said. "But you know what, I respect either one."

Harris has long identified with both her parents' ancestry. In Trump's remarks, some multiracial people saw echoes of their own experience of being asked to choose one or the other.

Harris' upbringing makes her a better leader for America, Democrats in Chicago said.

"When you have individuals who carry multiple experiences in the same person, that's an asset," said Representative Maxwell Frost, who is Lebanese, Puerto Rican and Haitian, speaking at a Politico event on the sidelines of the convention. "That enhances her ability to legislate and advocate" on behalf of a broad range of Americans.