Until recently, Andrea Ramirez, 43, thought she was part Mexican. But the results from an at-home genetic test from 23andMe revealed that she is a mix of Northern European, North African and a little Native American. And not at all hispanic. Ramirez, who hails from the Bay Area and works in marketing, bought the $199 genetic test in 2013 for a lark after her brother Danny's own test came back with some curious results. She and Danny are both fair-skinned and freckled, and don't closely resemble their half-siblings from their father's first marriage, but they never questioned their heritage. As expected, Danny showed up on a list of Andrea's DNA relatives on 23andMe. But his DNA was only about a 25 percent match with hers, meaning that he wasn't a full sibling as she had expected. More strangely, a mysterious woman also appeared on that list as a potential relative. This woman's profile stated that she was donor-conceived. And that's when it clicked for Ramirez. Her dad, the man who raised her, was not her biological father.

'A true ethical dilemma'

Andrea Ramirez

More people than ever before are expected to buy a DNA-test this Christmas from sites like AncestryDNA or 23andMe, as well as on Amazon.com. Millions have already gotten tested. And for many of these people, the results are unexpected, shocking, and occasionally even life-changing. The direct-to-consumer genetic testing market, which includes both health and genealogy tests, is expected to grow from about $70 million in 2015 to $340 million by 2022, according to a report from Credence Research. CNBC spoke to a dozen people who took a DNA test to find out fun facts about their ethnic roots, then were surprised to learned they were donor-conceived. That means the men who had raised them were not their biological fathers -- instead, their parents had faced fertility problems, and their mothers had used sperm from donors at a fertility clinic. Research from 2005 found that so-called paternity discrepancy, when a person is identified as being biologically fathered by someone other than the person they believe is the father, occurs between 0.8% to 30% in the population. All but one of the people who talked to CNBC asked to remain anonymous out of respect to other family members. Most of them don't regret learning the truth, but needed to have some tough conversations with their parents and were left with many unanswered questions. In some cases, they did find likely family members but that didn't always lead to a reunion. Some bio-ethicists say that 23andMe, Ancestry and the rest should do more to educate their users about the risks and potential outcomes. Making matters more complex is that a donor who wants to stay anonymous might decline to send in their DNA, but can still be traced through their family members. To its credit, 23andMe does warn its users in its terms of service that the information "has the potential to alter your life and worldview." AncestryDNA's website doesn't make that quite as clear, although it does stress that users might find unknown relatives. Others believe that fertility clinics should take additional steps to alert donors that anonymity is a thing of the past. Donors should know that if any of their family members get a genetic test, they could be found. Ramirez and many of the others who learned they were donor-conceived via a DNA test said they hope that the testing companies won't react to these stories by making it more challenging to identify and contact family members. "It's a true ethical dilemma," said Ezekiel Emanuel, chair of the Department of Medical Ethics and Health Policy at the University of Pennsylvania. As Emanuel explains, those that are looking for their donors have very legitimate reasons to want a relationship. But donors also have a right to privacy. "I honestly don't think we can satisfy everyone for all these cases," he said.

Andrea Ramirez with her mother and half-brother Andrea Ramirez

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