9 Investigates: Genetic surprises with home DNA tests

CHARLOTTE, N.C. — Home DNA tests have become such a popular purchase these days, you can find them in drug stores. But, what happens when test results are nowhere near what you expected.

Home DNA tests offer customers a window to their past, but as more Americans sign up with companies like 23andMe or AncestryDNA, the digital family trees they create sometimes reveal strangers.

Cynthia Keller was a customer with 23andMe and her test connected her to mystery relatives and revealed a secret -- the man she always knew to be her dad was not her biological father.

"It was really shocking. Shocking was the big word first, and then denial about how could this be," Keller said. "Once you take that test, you really can't unknow what you've just known or what you see. And it's important for people to know. It's a rollar coaster ride, there's a lot of grief involved."

Keller said she discovered her truth after her mother, the father she grew up with, and her biological father all died.

Now, she is writing a book about her experience.

Heidi Sposato, a therapist at the University of Central Florida, helps college students deal with what genenticists call "non-paternal events."

"With these ancestry tests, people usually do it for entertainment value," Sposato said. "It's for fun, it's for entertainment and they don't know that they're going to find some deep dark family secret that generations maybe have been covering up."

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She said there are even support groups on social media sites.

"At the end of the day, there are so many factors to consider. It definitely is not just one person's secret," Sposato said. "So, it is important to factor that in and think about, does the other family know? Are they waiting and looking for me, waiting for me to reach out?"

Ancestry DNA sent Channel 9 a statement after we asked about the frequency of non-paternal events.

A spokesperson said, "The company takes the potential impact of complex discoveries very seriously and they have a special unit dedicated to counseling customers.

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Keller said she tracked down the few biological relatives she could find with mixed reactions.

"I was very gingerly reaching out," Keller said. "Because I think it's very important not to bust into someone else's family and as an outsider that's what you could be doing."

She said it took about 18 months to absorb the shock. Keller said she now hopes to be an example and warning about what you might see in that window to your past.

"Basically, you feel like your life's a lie a little bit, you've got to get past it," Keller said. "You think 'Gee, everything that I knew growing up, I don't know what part of that is true anymore of isn't true.'"

One of the fastest growing online support groups is called "NPE Fellowship," which stands for "Not Parent Expected."

The organizer has now applied for nonprofit status, hoping for more resources to connect as many people as possible who are experiencing this type of discovery after taking a DNA test.

Cox Media Group