The Pentagon is advising members of the US military not to use DNA testing kits, warning that the popular genetic identification kits could pose a security risk.

Companies such as 23andMe and Ancestry allow people to get a breakdown of their genetic makeup and geographic heritage, from providing a saliva sample. Ancestry boasts some 15 million users, while 23andMe says it has 10 million.

But a department of defence memo, obtained by Yahoo News, warned that the kits could put members of the military at risk.

“Exposing sensitive genetic information to outside parties poses personal and operational risks to Service members,” wrote Joseph D. Kernan, the undersecretary of defence for intelligence, and James N. Stewart, the assistant secretary of defence for manpower.

The December 20 memo, which noted that some DNA kit companies have been targeting military personnel with discounts, appears to have been distributed widely within the Defense Department, Yahoo News reported.

View photos The Pentagon has warned against DNA kits More

“These [direct-to-consumer] genetic tests are largely unregulated and could expose personal and genetic information, and potentially create unintended security consequences and increased risk to the joint force and mission,” they wrote.

“There is increased concern in the scientific community that outside parties are exploiting the use of genetic data for questionable purposes, including mass surveillance and the ability to track individuals without their authorization or awareness.”

The memo reflects a wider concern about biometrics like DNA, fingerprints and facial recognition.

Erin Murphy, a professor at New York University’s School of Law, said a commercial genetic database could be used to unmask a person working undercover.

“It all boils down to the same basic idea,” she told the website.

“In a world in which a few stray cells can be used to identify a person, there is no such thing as a covert action, and no such thing as anonymity.

A spokesman for Ancestry said that they took measures to protect customers’ identities.

“Protecting our customers’ privacy and being good stewards of their data is Ancestry’s highest priority,” the spokesman said.

“Ancestry does not share customer DNA data with insurers, employers, or third-party marketers. Ancestry will also not share customer personal information with law enforcement unless compelled to by valid legal process, such as a court order or search warrant.”

23andMe did not respond to a request for comment.