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money. “It will go exponential very quickly,” he says.

Church also has an answer for those worried about a dysto-

pian future. In some communities, he points out, people are

already using genetic data to decide whom to love and marry.

MATCHMAKER, MATCHMAKER

Genetic matchmaking is simply a part of marriage for one Jewish

community. Decades ago, about 1 in 3,600 children born to

orthodox Ashkenazi Jewish parents were diagnosed with Tay-

Sachs disease, a rare, recessive genetic disorder that appears a

few months after babies are born. The disease progressively kills

nerve cells until the infant can no longer crawl or even turn over.

Eventually, the child dies.

The situation prompted scientists and community members

to come up with a plan. In high school, boys and girls have their

DNA sequenced. They’re assigned a number, but not told if

they’re a carrier of the disorder. Once a couple is ready to get

married, they send their numbers to religious officials, who

compare them. If neither person — or just one — is a genetic

carrier, they’re simply told that they’re likely a healthy match.

But if both carry genes for Tay-Sachs, the couple is informed

and given genetic counseling about their options. Thousands

of Ashkenazi couples go through the process every year, and

more than 4,500 have decided not to get married as a result. It’s

already helped reduce cases of Tay-Sachs significantly.

Church imagines a variation of this program for couples

everywhere. Existing social media and online dating sites could

be modified to implement this kind of genetic matchmaking at

a population scale — for all diseases.

In Church’s vision, these kinds of services would add in a

genetic screener. If a match might lead to offspring with a fatal

disease, you wouldn’t be shown that person. To ensure the

privacy of those screened out, a few people would be randomly

removed as well.

The prospect of giving up on love simply because an algo-

rithm has decided you may be unfit — like the Ashkenazi

model — might be a little much for some people. But that’s not

necessarily where such a system might lead.

“I don’t think people are going to do that,” says Stanford

University bioethicist Hank Greely, who specializes in the legal

and ethical issues of genetics. He says it’s silly to think you could

generalize from one tight-knit group to the rest of the U.S. “It’s

a very different culture from the rest of the country,” he says.

Instead, he suspects that if people did get their genome

sequenced, they might use the information to gauge their risk

of having children with genetic diseases. Then they might

decide to roll the dice, adopt, not have kids or use pre-screened,

implanted embryos.

Greely also downplays another common fear. It would be

almost impossible for people to use their genome sequences

alone to produce designer babies, he says. That’s because most

traits, like height or intelligence or even eye color, involve a huge

number of genes, many of which are unknown. By contrast,

many genetic diseases come from just a single gene.

And as far as discrimination from employers and insurance

companies goes, Church is counting on the Genetic Information

Nondiscrimination Act of 2008. The law made genetic discrimi-

nation illegal in the U.S., though it doesn’t cover some services,

like life insurance.

Church says no insurance companies would have access to

discriminatory information about patients’ genetic data. But

insurance companies, and even patients, wouldn’t necessarily

have to see the genomes to benefit, he adds. Software could play

matchmaker for family planning, tipping couples off to problems

and cutting rates of genetic diseases.

Furthermore, Greely says he’s not really worried about people

getting access to his genomic data, even though he doubts

Nebula — or any other company — can guarantee their data-

bases won’t be hacked. “I’m far more concerned with my credit

card receipts and Google search history,” he says. “Those say a

lot more about me and my life than my genes do.”

In the end, Greely says the biggest concern may be having

everyone walking around thinking about their genetic fates.

Armed with knowledge of your predisposition to a certain dis-

ease, you might be able to take preventive action. But for many

conditions, there’s no cure. “Do you really want to know all that

info?” he asks.^ D

Eric Betz is digital editor of Discover. He’s on Twitter: @ericbetz

Genetics 101

Tay-Sachs is a recessive genetic disease. That means, for the

disease to manifest, both copies of a gene must have the Tay-

Sachs mutation. Some people can be carriers for the disease:

They have one mutated copy, but their second copy is healthy

and dictates how that gene is expressed. But if two carriers have a

child, there’s a chance the child could inherit both mutated copies

from their parents and could end up with the disease. In some

communities of Ashkenazi Jews, who are at a higher risk for the

disease, there’s already a variation of genetic matchmaking to

prevent cases of Tay-Sachs.

Carrier

Carrier Unaffected

Affected

Unaffected

JAY Carrier

SM

ITH

Carrier Carrier

Carrier

Unaffected

Unaffected Carrier