Warning: If You Don't Want to Know the Results of a Genetic Test, Don't Take It


Genetic Testing

Giving his mother and father the gift of a 23andMe genetic test tore biologist "George Doe's" (alias) family apart. How? By discovering that he had a half-brother of whom he knew nothing. Doe tells his story over at Vox:

I have my PhD in cell and molecular biology. When I saw that I share about 22 percent of my genome with a person, I thought, "That's huge." It took a bit of time to realize Thomas and I actually share the same genome with my father. This is how it happened: when you share around 25 percent genetic similarity with someone, that means that either it's your grandfather, uncle, or half-sibling. 23andMe listed Thomas as a grandfather, which was confusing to me. I called my dad. All I had was his name, Thomas, and the fact that he's male. I just asked my dad, "Does this name sound familiar?" He said no. He logged into his account, and Thomas wasn't showing up at all. I was so confused. We figured out that at the very bottom of your profile, there's a little box that says "check this box if you want to see close family members in this search program." [Note: 23 and Me has since switched to an opt out system, where users will automatically be enrolled in the close relatives finder program.]

Dad checked it, and Thomas' name appeared in his list. 23andMe said dad was 50 percent related with Thomas and that he was a predicted son.

I freaked out. I said, "Can I call you back later?" I hung up the phone. I pulled out my genetics textbooks, called my contact at 23andMe, and asked if it was wrong. I called my sister and for three days, we agonized about what to do, we got into a fight, and thought. "Do we say something? Do we not say something?" Dad figured that because Thomas was listed as my grandfather, the company had made a mistake.

I reached out to Thomas over 23andMe and soon found out he had been adopted at birth and was searching for his birth parents for years. I immediately felt empathetic: he has his own daughter now, and they're going to the doctor and the doctor says, "Tell me about your family's med history," and he doesn't know anything. I thought, "He has a right to know. Who am I to stand in the way and say, 'You can't talk to my dad — it might hurt my feelings?'" …

At first, I was thinking this is the coolest genetics story, my own personal genetics story. I wasn't particularly upset about it initially, until the rest of the family found out. Their reaction was different. Years of repressed memories and emotions uncorked and resulted in tumultuous times that have torn my nuclear family apart. My parents divorced. No one is talking to my dad. We're not anywhere close to being healed yet and I don't know how long it will take to put the pieces back together.

After this discovery was made, I went back to 23andMe and talked to them. I said, "I'm not sure all your customers realize that when they participate in your family finder program, what they're participating in what are essentially really advanced paternity tests." People find out that their parents aren't who they think they are. They have nearly a million people in the database. If there happens to be anyone in there you're related to, they'll find your match. This is a solid science.

What's the right thing to do? I am a long-time happy customer of 23andMe and checking the DNA relatives section, the closest one is someone who shares with me 2.19 percent of their DNA as measured by the company—basically a 2nd to a 3rd cousin. The 23andMe DNA relatives site is now opt-out and begins with a warning:

DNA Relatives now includes all matches, including close relatives, allowing you to connect more easily with your family members on 23andMe. With continued participation in DNA Relatives, it is possible that you may discover unexpected close relatives.

If you do not want to be visible to close relatives, you may opt out of DNA Relatives. By choosing not to participate in DNA Relatives, you will no longer appear as a match for any of your genetic relatives.

You can opt in or out of DNA Relatives at any time from your Account Settings page.

Is that enough? I recall that when 23andMe reported the results of its test for APOE4 alleles* that dramatically increase the risk of Alzheimers disease, the company festooned the click button with all kinds of warnings telling the unwary to turn back if they feared to know. (Of course, that was before the FDA forbade the company to tell customers such data.) So I think that George Doe is right when he writes:

I would want a warning saying, "Check this box and FYI: people discover their parents aren't their parents, they have siblings they didn't know about. If you check this box, these are the things you'll find." And I'm the one with my PhD. I understand how this works. But I didn't think through all of the practical implications, in part because I thought, "This wouldn't happen to me."

But that's a just a temporary measure. And I suspect that most people will click the button anyway. The genetic information genie is out of the lamp.

*For what it's worth, I did want to know my Alzheimers disease risk and so clicked the button. With respect to those alleles my risk of Alzheimers disease is about half of the average for males of European ancestry according to the company.