Genetic Testing Can Tell You a Lot About Yourself—But What If You Don’t Want to Know?

This is DATA, a monthly column by Angela Chen on numbers, nerdery, and what it means to live an evidence-based life.

I knew what I was doing when I bought a 23andMe kit. I knew I would be giving my genetic information to a for-profit company that may or may not have nefarious plans for it. But I simply couldn’t resist. I loved information, and had always tried to gather it by any means possible.

My lust for knowledge went doubly for bad news, which I saw as a personal test of character. There was nothing, no matter how devastating, that I wouldn’t prefer to know. I would rather discover that everyone thought I was an idiot than believe I was even one tiny bit smarter than I actually was. Seeking out and being strong enough to bear even the worst news was a defining part of my belief system. To explain this to others, I trotted out the same two quotes every time. One was from Nietzsche: “I measure the strength of a spirit by how much truth it can take.” The other, often attributed to Carl Sagan, actually came from fantasy writer P. C. Hodgell: “That which can be destroyed by the truth should be.”

I happily spat into the little tube and mailed it off. Here, I thought, was the opportunity to know the most intimate truths about myself, information contained in every cell of my body. That day, though, I was motivated by little more than curiosity and narcissism. Everyone in my family was healthy. I had no reason to believe that my results might turn up anything worthy of worry.

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The promise of genetic testing is that the information in our DNA holds the key to a better life. It’s good to take medicine that fits our symptoms, but even better to take medicine that has the highest likelihood of working, according to our genetic makeup. “Eat food, not too much, mostly plants” is fine advice, but with a mouth swab and a couple hundred dollars, you can receive a meal plan customized for our specific arrangement of DNA base pairs.

Before we can have individualized meal plans, we need to know our genetic makeup—and this information is easier than ever to get. The Human Genome Project, which sequenced the letters of our genetic code, took eight years and cost nearly $3 billion. I paid $99 for my 23andMe kit, plus there was free shipping.

Genetic information holds enormous power over our lives, both how we live them now and what we can look forward to. It’s no secret that companies want this information, whether to help calculate appropriate insurance costs or to use in their own research. 23andMe has been criticized for selling patient data to pharmaceutical companies. In March of this year, a House committee approved a bill that would let companies compel their employees to undergo genetic testing and share that information with their employer. This bill likely won’t get far, but it’s a reminder of the weak legal protections we have when it comes to genetic privacy.

Sometimes lost in this debate is the question of whether we should always know. “If you imagine a world in which that information is always and automatically shared, you might be more hesitant to learn information about yourself,” University of Baltimore law professor Natalie Ram told me, “and that information can be deeply integral to how you view yourself and your connection to the world.”

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My results came back and revealed that I am 99.5 percent Han Chinese. My parents were born in the same central Chinese city and have known each other since first grade, so this was not a surprise. What I really wanted to know was not where my ancestors came from, but what kind of person I was.

With some data analysis and a guide aptly titled “How to Use 23andMe Irresponsibly,” I looked up health risks and, more importantly, certain interesting gene variants. There was the “warrior gene,” which the guide told me is overrepresented in violent criminals. I had that. There was the “adventure gene,” associated with doing lots of drugs and liking novelty. Check, though I sometimes eat oatmeal three times a day and don’t even drink. I lacked the gene variant correlated with both being gregarious and being able to pick up conversation in noisy places. (Accurate.) To my amusement, I also lacked the “divorce gene.”

Anyone serious about science knows that most of these correlations are tenuous and perhaps not much better than reading tea leaves. My five minutes of self-congratulation for being adventurous were harmless. But as this research becomes more widespread and more accurate, these tests could classify us, even just to ourselves, into more and more specific groups: the warrior group, the adventure group, the divorce group.

Classifications change us; change the world around us. Philosopher Ian Hacking calls this “the looping effect of humankind,” or, more poetically, “making up people.” The existence of the ADHD classification has affected how we view “normal” and “abnormal” childhood behavior. The existence of the multiple personality disorder classification led to more people manifesting these symptoms. As the technology progresses, we will have more and more opportunities to face many different types of news, and then we will need to figure out how much we want to know, the cost of knowing it, and what it means to say no.

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My mother is losing her memory.

I left for college before the symptoms really began to show. Thousands of miles away and never at home for more than a couple weeks, I was shielded from the daily reality of her problems moving beyond forgetfulness.

This ended when I was home for break one year, trying to work in the dining room. Behind me, my mother was tidying up the counter. I heard her pick up a glass, heard liquid sloshing. “Oh, Jessica must have forgotten to finish her milk,” she said. She set it down and went to do something else. Five minutes later, I heard her pick up a glass, heard liquid sloshing. “Oh, Jessica must have forgotten to finish her milk,” she said again. She set it down and went to do something else. I picked up my laptop and left the room. I did not want to hear her notice the glass a third time.

I don’t know what’s wrong with my mother. My family doesn’t know. Expensive Stanford University neurologists with three-month waiting lists don’t know. She’s only fifty. Brain scans come out normal, even as she fails the most cursory behavioral tests.

I have always had an extraordinary memory, the kind that people remark upon, the kind notable enough to build part of my identity on. I already took that genetic test, and nothing showed up. But because I am very like my mother—moody, ambitious, and, when she was younger, in possession of an extraordinary memory herself—I can’t help but wonder if the gift she passed to me comes with the same catch, and whether I would want to know if it did. Underneath the fears for my mother’s health and my father’s ability to cope lurks the selfish dread that what happened to her will someday happen to me.

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Huntington’s disease is a fatal, incurable condition that starts to show symptoms—motor problems, depression, mental confusion—in middle age. It’s a dominant gene, so those with one parent with Huntington’s have a 50 percent chance of having the disease. That’s a 50 percent chance they, too, will spend the second half of their lives losing control of their body and mind. You can find out the answer with a genetic test that’s been around since the nineties.

Not many people at risk for Huntington’s choose to undergo genetic testing—fewer than 10 percent, according to a sample from one study published in the American Economic Review. The researchers conclude that the emotional cost of testing, and having their positive illusions shattered, may be so high that it outweighs the value of testing. This makes intuitive sense: Let us have a happy life for a little while longer. We’ll cross that bridge when we get there. There’s an entire documentary about this “agonizing decision.”

Many of the people who get tested do so only once symptoms start emerging, to prove their worst fears. But because you can take the test anytime, there is another debate too: whether children who could be at risk, who wouldn’t start exhibiting symptoms until forty or later, should be tested. Some insist they ought to know as early as possible. Others ask, If a happy life can be destroyed by the truth, should it?

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My family was driving to dinner one night last year when my dad mentioned my mother’s memory problems. She has trouble driving because she gets disoriented. She needs a day-of call to remember appointments, even if there are calendar and phone reminders. She’s left the stove on.

I’m fine, I’m fine, my mom said. I’m fine. Just a little forgetful.

I grit my teeth at these words. All our lives would be easier if she just faced the truth, I thought, just like I had always faced the truth; even actively sought it out.

But her life might not be easier. If my mother isn’t ready for the repercussions of that knowledge now—and who would be?—perhaps the price is too high. Perhaps it is best for the rest of us to follow her lead, play along for as long as we can.

Just as those at risk for Huntington’s must weigh the consequences of knowing and decide whether or not to undergo genetic testing, how my mother chooses to face her own unknown future is an intensely personal decision. I can’t say for sure what I would do if I were offered a test that would tell me whether I will also lose my memory someday. But from my experience with my mom, I now understand the value of not having every single piece of information, when some would suck too much joy out of the rest of your life. And for what? It’s a delicate emotional calculus that people must work out for themselves.

Maybe there is something more important than forcing yourself to face the truth at every turn. My mother’s problem is a big one, but my experience with her has affected how I view the smaller decisions in life, too. Maybe there is some value in believing in a slightly rosier version of the world than is true, in believing that I am a little more beautiful than I am, in believing my future doesn’t hold a quick slide into early senility. Maybe it’s true that if you measure the strength of one’s spirit by how much truth it can take, mine is not as strong as I once believed—and maybe that’s okay, because there are more important things than being strong.

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