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.