How a Third Cousin Could Give Away Your DNA Secrets

Relatively simple tests that can analyze an individual’s DNA have proved a boon in the fields of medicine and criminal justice, not to mention genealogy. They can identify genetic disorders, implicate or clear criminal suspects, and help people fill in their family trees. In recent years, however, it’s become clear that DNA data can be used in ways we never expected or desired. As a result, more people have begun to worry about what might happen to their most intimate personal information.

1. Why should I be concerned?

It’s difficult enough to know how your DNA data might be used now, let alone in the future. And unlike a bank account number or a password that can be changed, once it’s out there, it’s out there for good. There are obvious reasons for companies such as insurance providers to take an interest in your physical makeup. The U.S. military in 2020 advised its personnel against using consumer tests, in part because a result showing a marker for disease could both be inaccurate and stymie a career. Your genetic data could reveal information you might not want public, such as an unacknowledged parental connection. If you’re a lawbreaker, or so much as distantly related to one, there’s the fact that law enforcement agencies increasingly rely on DNA data to solve difficult cases. Also, the tests can reveal a person’s ethnicity, which can be dangerous in some contexts.

2. How so?

In China, the government has taken DNA samples from citizens under the guise of free medical exams and built a genomic database of some 100 million profiles, according to the quasi-governmental Australian Strategic Policy Institute. It says data were collected from nearly every resident of the province of Xinjiang, where China says it’s fighting extremism among Uighurs, a Muslim ethnic group. As many as 1 million Uighurs have been detained in internment camps, according to the United Nations. When officials in Hong Kong offered coronavirus testing to the city’s entire population in September, suspicions were raised that DNA data would be harvested from samples; authorities denied it.

3. How are other governments using DNA data?

Seventy countries report that they maintain a national DNA database, which can help identify crime suspects and convict or clear them of charges. In recent years, police in the U.S. have gone beyond their own databases to solve crimes based on consumer DNA test results. They’ve taken DNA from a crime scene, compared it to the DNA of people in a commercial database, then identified a suspect among their relatives. Most commercial testing companies say they require a warrant to let police access customer data. But in 2019, a Florida judge granted a warrant giving police access to the entire database of GEDmatch, a free service that lets genealogy hobbyists upload their data from other companies to find more relatives.

4. Who else can access my DNA data?

In the European Union, in some cases your data can be shared without your consent if the purpose is scientific research that’s in the public interest and the data are anonymized, that is, stripped of information such as your name and contact details. In the U.S., results of tests taken in a medical setting can be shared if they’re anonymized. Commercial DNA testing companies in the U.S. are bound primarily by their own terms of service. Generally, these companies share anonymized individual data with contractors that help process it and, if you provide additional consent, with academic and drug company researchers. They also often share aggregated data.

5. Doesn’t anonymizing data protect my identity?

Not necessarily. Your DNA is inherently identifying; it’s a code that’s unique to you. And it doesn’t have to be stored with your name to be connected to it. Research has shown that it’s possible to discover the identities of anonymous people who participate in genetic research by cross-referencing their birth date, sex and postal code, for instance, with publicly available information. Also, databases can be hacked. Testing company Veritas suffered a breach in 2019 exposing customer information, though not genetic data, it said.

6. Can my data be used to discriminate against me?

There are some legal restrictions. In the U.S., a 2008 law called the Genetic Information Nondiscrimination Act (GINA) aims to protect against discrimination by employers and some insurers on the basis of genetic data. But gaps in GINA mean that providers of life, disability and long-term care insurance legally can compel you to share findings about your DNA. And they can make decisions based on the data, though there’s no evidence this has happened.

7. How can I keep my DNA data private?

It may be too late for that. A bunch of other people have DNA that’s almost identical to yours. So if a third cousin you’ve never heard of puts his DNA out in the wild, yours is out there too. One study suggested that just 2% of people need to share their genetic information for virtually everyone to be identifiable. Since there is little hope in keeping our genetic information private, experts have begun calling for more regulations to ensure the data are not abused.

The Reference Shelf

  • A white paper by Consumer Reports on privacy issues raised by DNA tests.
  • The Electronic Frontier Foundation surveys U.S. laws affecting privacy of genetic information.
  • Bloomberg Businessweek explores the intersection of DNA data and law enforcement.
  • A Bloomberg reporter describes taking a DNA test in China.
  • Human Rights Watch reports on China’s project to collect DNA from citizens.

©2020 Bloomberg L.P.

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