Of the total genetic diversity of the human species, only seven or eight percent can be attributed to differences based on "race"--that is, skin color and other physical characteristics. Compare that with the 85 percent of genetic diversity that can be found between different geographic groups within a race... "In other words, pick out two white people on the street, and they'll have more genetic differences between them than with a randomly picked black person," says Phil Klinkner, author of The Unsteady March: The Rise and Decline of America's Commitment to Racial Equality.