Cheryl has bought 16 kits from 23andMe, two for her (after her first one, she bought an updated version) and 14 on behalf of her friends and family. For each of them, she asked their permission and explained what she wanted to use the data for. But nobody ever read the forms.

Still, not everybody is interested in playing the genetic genealogy game. When Cheryl asked her daughter Wendy’s husband, Dennis Plear, if he’d like to test, he flatly refused, and also forbade Wendy from having their children tested. Dennis, a disabled Navy veteran who is half African American and half German, is wary of such personal information winding up in the hands of the government.

“When you start giving out samples of your DNA, you’re opening the door for other people to be in your business,” he says.

When told that these companies purport to be keeping the information secure and out of reach of third parties, Dennis wasn’t impressed. “If you have it on file, on the internet, the government has access to it one way or another.”

But for every customer deterred by privacy concerns, there seem to be many more who don’t care. Genetic genealogy databases are growing every day, and that pace will quicken as the costs of genetic sequencing drop.

It’s plausible that in the not-too-distant future, we’ll all be identifiable in genetic databases, whether through our personal contribution or that of our relatives. Some ethicists have called for federal legislation to restrict these kinds of collections. But many scientists, including Erlich, are against that idea, pointing out that genetic databases can be used for good—not only for genealogy, but for medical discoveries. “We cannot change the course of technology,” Erlich says.

Instead, he says, regulation should focus on preventing harm to individuals. For example, the Genetic Information Nondiscrimination Act (GINA), passed in the United States in 2008, says that health insurers and employers cannot use an individual’s genetic information to deny medical coverage or to make employment decisions. “GINA was a good step forward,” Erlich says. “It’s not about having the information— it’s about not abusing it.”

§

FROM HER TRAINING AS A NURSE, Cheryl is aware of the need to respect other people’s privacy. So in May of this year, when she first reached out to Effie Jane, she was wary of divulging too much, saying vaguely that she was interested in the Parker family line.

About a week later, Effie Jane wrote her back saying she would be happy to talk to her. Over the next couple of weeks, Cheryl and Effie Jane shared many emails and phone calls, and discovered that they had a lot in common.

“I never felt like I was a part of my family,” Effie Jane says. Her ruddy complexion and crystal-blue eyes look like Cheryl’s, but that’s the extent of their physical resemblance. Their childhoods, though, were similarly traumatic. Effie Jane started having seizures at six months old, and at 14 her mother died. Her father, Joseph Parker, like Cheryl’s adoptive father, Joe, was cold and indifferent, and “may have had a little mental imbalance,” Effie Jane says. After her mother died, his personality changed; for example, he instructed her to start calling him “Mr. Parker” rather than “Daddy.”

Effie Jane has felt rejected her whole life, but found acceptance in Cheryl. “I had always prayed for a sister,” she says. After meeting for the first time at Panera, the women kept talking, and slowly began to broach the sensitive subject on both of their minds: If they were indeed sisters, then how would Vivian have known Mr. Parker?

Mr. Parker was a train engineer, and would often be away from home for days at a time. Vivian frequently took the same train he worked on to vacation with her family. So she could have known him for years. Or perhaps she met him just once. Maybe they were friendly; or, who knows, maybe she was raped. These were the theories that Cheryl and Effie Jane tossed around. They wouldn’t know for sure until the test results came back. But Cheryl felt in her gut that this was the one.

“I’m feeling really comfortable with where I’m going with this. I feel like I’m going to find answers soon.” That’s what Cheryl said to me during our first phone interview, in early July. She had been anxiously tracking the shipment of Effie Jane’s kit and knew that it had arrived at 23andMe that Saturday. She had just a few weeks to wait.

Effie Jane and Cheryl

Cheryl and Effie Jane’s relationship blossomed over that period. As Cheryl described in an email to Sandi, “There are a lot of things about Effie that seem familiar to me, as though we are of the same cloth.”

Cheryl and Effie Jane went to the cemetery where Mr. Parker is buried and snapped photos of his plaque. They also attended an all-day church workshop put on by Cheryl’s son, Travis, about how to deal with rejection. “My mom has a hard time believing that we accept her,” Travis says. “But that’s because of the deck of cards that she’s playing with.”

On July 23, Cheryl wrote to me with the surprising verdict: Effie Jane was not her sister. She was not even a first cousin once removed, as Diane had guessed. The genetic test estimated them as fourth cousins, at most, with just two shared segments of chromosome.

I asked Cheryl how she was feeling about it, and her response read, to me, like she was trying to hide her disappointment: “I am good! I am frustrated, as now we will have to find someone else to test, and wait yet again!”

Effie Jane took the news in stride. “I didn’t cry. I didn’t have that feeling of being deserted by her,” she told me. And the fact that you don’t share much DNA, does that change how you feel about your relationship, I asked. “As far as I’m concerned, she’s my little sister.”

Cheryl, too, says she will probably be lifelong friends with Effie Jane. But there was still a hole in her personal history. And it needed to be filled.

§

EFFIE JANE’S TEST RESULTS WEREN’T WHAT Cheryl was hoping for, but they did help her and Diane to focus on the relevant part of Jeannette’s family tree. Diane quickly identified another man as Cheryl’s potential father, and Cheryl tracked down the phone number of the man’s daughter, Rose.

Cheryl called Rose one morning in late July. The conversation went surprisingly well. “She said, ‘Oh, are you saying you might be my sister? Oh, I hope you might be my sister!’” Cheryl recalls. Rose agreed to take a 23andMe test, and they tentatively planned to get together the following day to do the spitting.

Late that evening, Cheryl had an upsetting phone call with Rose. The DNA test had been weighing on her the entire day, Rose said, and she had decided she didn’t want to tarnish the memory of her father by taking it. “Of course I was in tears,” Cheryl told me the next morning. “It’s like another rejection.”

Cheryl says she understands how Rose must be feeling. “I am nobody to them.” She is now trying to decide whether she should reach out to Rose’s late brother’s wife, to ask if her children might get tested. Cheryl knows that Rose would be upset if she did that; on the other hand, there may be no other way to find out who her father is. “It will make me feel more complete to know who I came from.”

Though she doesn’t fully realize it, Cheryl is playing out the hypothetical scenario painted by bioethicists: How does one person’s right to know stack up against another’s right to privacy?