Take Caution: DNA expert warns of genealogy testing, privacy issues

SACRAMENTO, Calif. (KGO) -- ABC7 News spoke to a DNA expert who says the public should think long and hard before completing an at-home DNA testing kit.

"When you provide them with a sample, they have all your DNA," said Bicka Barlow, a San Francisco-based defense attorney who specializes in DNA cases.

RELATED: DNA that cracked 'Golden State Killer' case came from genealogy websites

She adds that people should be cautious of at-home genealogy testing services. Companies like 23andMe and Ancestry.com have become very popular, selling millions of DNA testing kits.

"I don't think it's safe," Barlow added.

A partial DNA match, with an unidentified relative of Joseph DeAngelo on a genealogy website, lead to his arrest. Barlow sees parallels between the privacy concerns and issues of social media companies and DNA testing kits.

"The fact that people got access to millions of people's information through Facebook would not be dissimilar to the police getting access to DNA profiles," said Barlow.

But isn't tracking down an alleged serial rapist and killer through DNA a good thing?

Barlow argues that DNA evidence "is not fool proof" and that new technology is actually increasing the chance of misidentifying people with DNA.

"When you did DNA testing back in the good old days you would get a single profile of one individual and that makes it quite easy to do a comparison," Barlow told ABC7 News. "But nowadays, the tests are so sensitive that crime labs come up with mixtures, meaning multiple people in a sample, somewhere around 70 to 80 percent of the time."

RELATED: Expert weighs in on case-cracking 'Golden State Killer' DNA evidence

Barlow says you need to consider your whole family before using a DNA testing kit.

Here is a full statement from 23andMe on the "Golden State Killer" case: We have not received inquiries regarding this case. Broadly speaking it's our policy to resist any law enforcement inquiries with all legal and practical means at our disposal. We have had a handful of inquiries over the years, and have never given customer information to law enforcement officials.

We don't know how California police identified this person, but it wasn't through our database. We didn't work with law enforcement on this case, they didn't contact us.

Here is the full statement from Ancestry.com on the "Golden State Killer" case: Ancestry advocates for its members' privacy and will not share any information with law enforcement unless compelled to by valid legal process, such as a court order or search warrant. Additionally, we publish law enforcement requests in our transparency report annually. It's important to note that in all of 2015, 2016, and 2017 we received no valid legal requests for genetic information.

At this point, DeAngelo has only been charged for two counts of murder for the death of a Sacramento area couple in 1978, but police promise more charges.

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