This is a question that's come up many times in the blogosphere. My own answer is "yes," humans races/populations/demes/subspecies do exist.
Human
Is Race a Biological Concept?
Genetically Speaking All Races Are Equal
Changing Your Mind: Maybe Human Races Do Exist After All
Matt Nisbet Asks an Embarrassing Question
Genetics and Race
Greg Laden on "Race" (Again)
Anne Wojcicki's Politically Correct View of Race
The Problem of Race .... Again
Human Races
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