How Accurate Are Home DNA Ancestry Kits? Investigation Uses Triplets to Put Companies to the Test

You'd think triplets would have the same ancestry. Not according to some of the results.

Millions of people are buying home DNA tests that claim to unlock the secrets of your ancestry, but an investigation has found some of the kits aren't always accurate.

Inside Edition wanted to see what the results would look like for identical sisters. A set of identical quadruplets and three sets of identical triplets took part in the investigation—which will air in full on Tuesday—by submitting their DNA to a selection of companies.

Read: FakeABaby.Com Provides Positive Pregnancy Tests and Sonograms, Some Use It to Dupe Their Lovers

A DNA testing expert told Inside Edition that "because these sets of identical sisters all came from the same fertilized egg, their ancestry should be absolutely identical," but surprisingly, not all of the results came back the same.

Among the triplets were the Maynard sisters, who were once on “American Idol." They sent their swabs to a company called “Family Tree DNA."

Incredibly, their results showed British Isles ancestry ranged from 59 percent to 70 percent among the sisters.

In addition, one triplet's results said she was 6 percent Scandinavian, while the other sisters were zero. For Western and Central European, one sister was 11 percent and the others were zero.

“Family Tree DNA” told Inside Edition that since our test they have improved their method of calculating the ancestry of their customers. The new method will be implemented in the next several weeks, they said. In mid-March, they will be rerunning their entire database and post updated results, they said.

Read: How a Routine Trip to the Dentist Can Put Your Life at Risk

Inside Edition also put other companies to the test with help from different sets of siblings.

One set of identical triplets included Erica McGraw, who is the wife of Jay McGraw -- Dr. Phil McGraw’s son and executive producer of the TV show, “The Doctors.” She and her sisters used a test from another company.

A third set of triplets and the quadruplets also used different testing kits. To find out how accurate their DNA ancestry results were, tune in to Inside Edition on Tuesday, February 21.

Check for local listings here.

Watch: Investigation Discovers Some Hotel Rooms Have Hidden Cameras