There's a reason we'll never come to a consensus on the most accurate racial classifications for Barack Obama or Tiger Woods. There's a reason questions about ethnicity on the census and college applications feel impossible to an increasing number of Americans. There's a reason you can be black in the United States, colored in South Africa and something else entirely in Brazil.

According to Dorothy Roberts, author of Fatal Invention: How Science, Politics, and Big Business Re-Create Race in the Twenty-First Century, it's because, despite centuries of efforts to treat race as if it's a biological category, it is no more than social construction -- created to oppress people -- that changes with place, time and perspective.

The Root talked to Roberts about the profit that's behind the re-emergence of myths about race, the impact for African Americans and health, and how we can continue to talk about it, minus the long-standing lies.

The Root: Fatal Invention is an attempt to correct major misunderstandings and myths about race. Explain what race is and what it isn't.

Dorothy Roberts: I can say very definitively that race is an invented political system; it is not a natural biological condition of human beings. The human species is a single race. It is not biologically divided up into distinguishable races.

TR: If there's no biological basis, why do the groups that we think of as different races look different? 

DR: Race is a political grouping that uses various biological demarcations that help distinguish who belongs to one or another. But those -- skin color, hair color, the shape of the nose or the lips -- are only part of what we use to determine what race someone is.