When she was an infant, Karen Heiting was abandoned on a doorstep of a church in downtown Chicago.
She wasn't born in a hospital, and she had no identifying information. She was "Jane Doe."
"There was no information whatsoever about my heritage," said Heiting, who was adopted when she was 7 months old and is now a 57-year-old executive assistant living in a Chicago suburb. "I never thought I'd find any relatives."
Just until a few years ago, many family trees were created by interviewing older relatives, an option not available to Heiting. But today, she was able to swab the insides of both cheeks and send her DNA to ancestry.com.
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Heiting was shocked to discover that she had blood relatives who looked just like her and that a family reunion was in order.
"There was a party with all the cousins, and everyone wore a name tag saying how they were related to me," Heiting said. "To walk in and look at my half-brothers' faces, and eyes and bone structure – it was so overwhelming for me to see these people."
People across the globe are using DNA companies, including 23andMe, MyHeritage, Ancestry and Family Tree DNA, to find relatives – in addition to creating digital family trees that go back hundreds of years. And while DNA tests at the doctor's office may cost upwards of $400, these are typically less than $100 and are just as accurate, said Jennifer Stagg, a naturopathic doctor in Connecticut and author of "Unzip Your Genes."
"These tests are really accurate, and the technology is pretty advanced," Stagg said. "The equipment is less expensive now, and with the volume, that always brings down the price."
James Pylant, Texas-based editor of Genealogy magazine, has tried tests from 23andMe, MyHeritage, Ancestry and Family Tree DNA.
The tests confirmed the accuracy of his paper trail, and in some cases, it was the missing piece of his family tree puzzle: It proved his family's kinship to Abraham Lincoln, Pylant said.
"I've also used DNA to answer questions about the people held in slavery by my ancestors," he said. "I've located living descendants of slaves and offered to give them DNA test kits. Our families share a historical connection, but are we also blood relatives?" he asked.
Every time someone submits DNA through one of the tests, it's uploaded into the system, so as each company grows, users have a better chance of finding matches.
MyHeritage, for example, has 93 million global users and has created 39 million family trees via 8.3 billion historical records, said Rafi Mendelsohn, spokesman for the company.
"Our system scans the other family trees to see if the names on your tree are on their trees, and we match them, so we organically match and expand," Mendelsohn said.
While similar technology is used for each company, they offer slightly different services.
MyHeritage includes all sorts of family history records, such as yearbooks and newspaper clippings.
After adding his own DNA, Mendelsohn (yes, he learned that the Felix Mendelssohn, composer with a slightly different spelling of his name, is a distant relative) received a newspaper article about his late grandfather's basketball team's victory.
"I shared it with my family, and it's a family heirloom," he said.
Family Tree DNA is one of the tests that offers the Y-DNA test, so you can discover more about your direct paternal or maternal line, Pylant said. The Y-DNA test is based on the Y chromosome that the father passes to the son (so it only applies to men taking the test).
"This test is helpful when trying to learn if two men with the same last name or similar surname share a common ancestor," Pylant said.
It also offers the mtDNA test, which looks at the mitochondrial DNA that a mother passes to her sons and daughters, though the son can't pass his inherited mtDNA along to his children.
Other tests are known for their shear size. Ancestry.com existed as the leading commercial genealogy site long before it began offering DNA kits, so a larger percentage of kit buyers had already uploaded family trees to their accounts, Pylant said.
Still, all four offer autosomal DNA kits, and users can find matches and the estimated ethnic origin of their parents on any of them.
Dominick Miserandino, a consultant in Long Island, had always been curious about his family history, so he submitted his DNA to ancestry.com. He learned that his old baby sitter was his eighth cousin, and he took a trip to Canada to reconnect with other distant cousins he'd discovered.
"Since then, we've been very much in touch, we FaceTime and we've had these great moments," Miserandino said.
But the information others receive has been shocking.
Tracy Tennant had always believed that a certain man was her father, based on the information her late mother had given her.
Although she never met her father, his name was on her birth certificate – and in 2014, two years after her mother died, Tennant reconnected with him.
But in 2016, she and her father took a DNA test and learned that they weren't related.
"My mother had been keeping a secret all those years," Tennant said.
Her real father had been a married, failed Hollywood actor who had died in the 1980s, and through ancestry.com, Tennant also learned that she had half-sisters.
Be prepared for anything. Your friends may become family in an instant. Or your family could be unrelated to you with just one swab.