I'm a stem cell and reproductive biologist. I fell in love with biology when I was in high school. It was the realization that every cell in my body has the same genome and DNA, but each cell is different. A stomach cell is not a brain cell is not a skin cell. But they're reading from the same book of instructions. With 23andMe, you get your personal genome book, your story. Unless you have an identical twin somewhere, that genetic makeup is unique to you.

Last year, I taught a course about the genome. For one of the lessons, I demonstrated the process of acquiring a tissue sample — in this case saliva — and sending it off to 23andMe to look at a million letters in my genome. 23andMe analyzes them, and spits out a report telling you things about yourself at the genetic level. Then you get the awesome bonus of learning about your ancestry: finding out which parts came from Europe, Africa, Asia.

I had spent many years looking at the genes of other animals — particularly mice — but I never looked at my own. Because I was so excited about it, I got two 23andMe kits for my mom and dad as gifts. It's a lot more fun when you can incorporate your family because you can trace not just the chromosomes but individual alleles on the chromosome so you don't just see them, but where they came from. Also, I felt I had a good handle on my family's medical history so I was very interested in confirming any susceptibility to cancers that I heard had run in my family, like colon cancer. I wanted to know if I had a genetic risk.

I found out I don't have any genetic predisposition to any kind of cancer, which was a great relief to me. But I also discovered through the 23andMe close relative finder program that I have a half brother, Thomas.

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."



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?'"

"Years of repressed memories and emotions uncorked and resulted in tumultuous times that have torn my nuclear family apart."



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, 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.

The person I spoke to didn't really have a response. I don't want to say she was aloof. She just said "that's interesting." I also wanted a response about the grandfather prediction for Thomas. We all know that genetically it's hard to distinguish a son from a grandfather, but I don't think she realized what a big deal that is to get it wrong.

I don't want to say if I knew that I wouldn't have participated. But I'm really devastated at the outcome. I wrestle with these emotions. I love my family. This is nothing I ever would have wished. My dream would be to introduce Thomas to dad, to incorporate a new family tradition, to merge families. We all get to broaden our horizons and live happily ever after. At least right now, that's not what happened. I still hold out hope that in time we can resolve things. But I also worry that as these transitions happen there may have been some permanent emotional damage that may not be able to be undone.

23andMe's way of protecting people is by giving users the chance to click that box to opt into the relative finder program. I think they're trying to protect people from themselves. They believe in the power of information and of learning about yourself. Some people can't handle the information. Some people don't even know they can't handle it.



When you check that [close relatives] box it should have a bunch of stars and bells and whistles around it. Because there are plenty of people who click boxes. Nobody reads their iTunes agreement. That's how I feel about the family finder thing: you just check all the boxes, just keep doing it, and never put a whole lot of thought into the possibilities.

"I would want a warning saying, 'check this box and FYI: people discover their parents aren't their parents and they have siblings they didn't know about.'"

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."



The irony has not escaped me that I gave 23andMe to my parents as a gift. In my own mind, the breakup of my family has been very difficult. I talk to a counsellor regularly now. It's helpful for me to see how I deal with these issues. I had to deal with the time that I essentially gave my parents the gift of divorce.



If I had never done that, nobody would be the wiser. I thought it was a cool gift. I am a lover of science, specifically biology and genetics, and just thought I was sharing that with my family who has always wanted to understand more about what I do and love. I don't know that I would have shared if I knew this would have been the result.



One of my favorite phrases is sunlight is the best disinfectant. I still think that's true. But this has challenged that worldview. This is an example where having more information has had a negative emotional and psychological impact on me and family relationships.

–as told to Julia Belluz

EDITOR'S NOTE: "George Doe" is an American biologist who used the direct-to-consumer genetic testingservice 23andMe as part of a course he was teaching on the genome — and made a surprising discovery about his family in the process. All the names and places here have been changed to protect the privacy of George's family, though the details of their story remain intact. Read more about how genetic testing affects families here.