The Department of Homeland Security (DHS) will next week implement a pilot DNA testing program at the U.S.-Mexico border in order to help identify people “posing as families,” according to a report from CNN.

The program, known as Rapid DNA, will run for two to three days at two separate locations on the border. It uses a cheek swab and can produce results in roughly 90 minutes.

The Trump administration has repeatedly warned of human traffickers forming “fake families” and falsifying documents to enter the country between ports of entry. “Cases of ‘fake families’ are popping up everywhere. And children are being used as pawns,” former Homeland Security Secretary Kirstjen Nielsen in a speech last month.

With the dramatic increase in the number of family units arriving at the border, DHS — which was set up to handle single men from Mexico, not families — has decided that DNA testing is the most efficient way to handle ensure families are not falsifying their documents.

Immigrations and Customs Enforcement (ICE) and Customs and Border Protect (CBP) will both be involved in the program, with CBP referring cases to ICE’s Homeland Security Investigations (HSI) division, which deals with issues related to human trafficking.

“CBP is always evaluating whether tools, such as DNA testing, can further enhance efforts to protect children,” a CBP official told ThinkProgress in a statement. “At this time, DNA testing has not been deployed to the field and no DNA has been collected.”

ICE has not responded to a request for comment.

But the process could have adverse effects. There are concerns over whether certain familial relationships — like an aunt and her nephew, for example — would constitute a valid relationship in the eyes of the federal government. There’s also the issue of privacy concerns. Misuse of data has led to wrongful convictions. Some researchers are concerned that these families, who are primarily from Central America and speak indigenous dialects, may not fully understand the concept of DNA testing well enough to give informed consent.

“We’re talking about populations of indigenous people,” Ysabel Duron, founder of the Latino Cancer Institute, told TIME last year, after the government began using DNA testing in an effort to reunite families it separated. “We don’t even know if some of them come from certain tribes, where they could have beliefs against DNA testing.”

During the aftermath of family separation, private DNA testing companies like 23andMe and MyHeritage offered to help reunite separated children with their parents. At the time, immigration activists working on the family separation crisis like the Refugee and Immigrant Center for Education and Legal Services (RAICES) and the Texas Civil Rights Project vehemently opposed the plan.

“These are already very vulnerable communities, and this would potentially put their private information at risk,” Jennifer Falcon, communications director at RAICES, told KQED. “Essentially we’re solving one violation of their civil rights basically with another.”

While agency officials said the tests were cheek swabs, some immigration lawyers at the time reported that their clients had been ordered to take blood and saliva tests.

This story has been updated to include a statement from CBP.