The Pentagon has issued a directive advising military members to beware of the growing popularity of the home DNA and ancestry kits, as they pose a higher security risk for military members than for their civilian counterparts.

The home kits are growing in popularity and are at this time of year a popular Christmas gift so that people can trace their ancestry. So far, in a study conducted by the Massachusetts Institue of Technology (MIT), over 26 million people have voluntarily sent their DNA to be tested. That number is expected to skyrocket to over 100 million by 2021.

That’s what worries some Pentagon officials. Under Secretary of Defense for Intelligence Joseph Kernan and acting Under Secretary of Defense for Personnel and Readiness James Stewart, said in a memorandum dated December 20, that DNA testing companies were targeting military members with discounts and other undisclosed incentives.

“These 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,” the memorandum read. “Tests that provide health information have varying levels of validity, and many are not reviewed by the Food and Drug Administration before they are offered.”

“Moreover, there is increased concern in the scientific community that outside parties are exploiting the use of genetic materials for questionable purposes, including mass surveillance and the ability to track individuals without their authorization or awareness,” it stated, but gave no explanation of how this was being done.

Several of the more popular companies, Andcestry.com and 23 and Me which have targeted the military community with discounts, have publicly commented that they do not share their data with third parties, employers or insurance companies without explicit consent forms from the individuals.

But consumer advocates warn all users, not just military ones, that their data can be sold by these companies in a variety of ways. It has been reported that some other companies have sold their data to third parties as well as law enforcement organizations.

However, back in July, the Navy’s Chief of Naval Operations, Admiral John Richardson, cautioned military members about using these DNA kits as he said scientific advancements are making biological weapons easily tailorable.