13 Things - Surprising Facts About At-home DNA Tests

If you send your DNA to two different companies to find out your ancestry, you may end up with two different results.

- Michelle Crouch

1 If you send your DNA to two different companies to find out your ancestry, you may end up with two different results. That’s because there’s no certification required for DNA-testing companies, and their methods aren’t independently validated, says Tufts University professor Sheldon Krimsky, PhD, board chair of the Council for Responsible Genetics. “They may get the basic idea correct—that you are a little less than half northern European, for example,” he says. “But when they say you’re 30 percent from here and 60 percent from there, it’s a statistical guess based on their own proprietary database and the statistical method they use.”

2 Your results will be less precise if you’re not European. The more people from your ancestral region in a company’s database, the more accurate your results will be, says Hank Greely, director of the Center for Law and the Biosciences at Stanford Law School. Many Americans have northern and western European ancestry, and some evidence indicates they’re more likely to use DNA testing. “Even results from southern and eastern Europe aren’t as accurate,” Greely says.

3 If you’re Native American or African American, no DNA test can tell you what tribe your ancestors belonged to. Testing companies that claim they can are misleading you, says Greely.