A

t least two dozen companies now market “genetic ancestry tests ” to help consumers reconstruct their family histories and determine the geo-graphic origins of their ancestors. More than 460,000 people have purchased these tests over the past 6 years (1), and public interest is still skyrocketing (1–4). Some scientists support this enterprise because it makes genetics acces-sible and relevant; oth-ers view it with indiffer-ence, seeing the tests as merely “recreational.