This holiday season, more people than ever before are giving the gift of spit. Well, what’s in your spit, to be precise. Want to know where your ancestors once walked or whether you’re at risk for a genetic disease? There’s a spit tube kit for that. And customers are buying them in record numbers.

Between Black Friday and Cyber Monday, leading personal genomics company AncestryDNA sold about 1.5 million testing kits designed to provide insights into your ethnicity and familial connections. That’s like 2,000 gallons of saliva—enough to fill a modest above-ground swimming pool with the genetic history of every person in the city of Philadelphia.

Ancestry says it’s equipped to deal with the impending deluge, but the flood of consumer interest has its executives eyeing the long-term prospects of their stretched supply chain. It also has some policymakers and public health officials concerned about the pace with which people are blindly giving away their genetic data to these types of companies, who can turn around and sell it to third parties.

At a press conference on Sunday, Senator Chuck Schumer (D–New York) called for increased federal scrutiny of the privacy practices of consumer DNA testing companies like Ancestry and its chief rival, 23andMe. The Food and Drug Administration regulates consumer DNA tests related to health, like the 23andMe panel it approved earlier this year. So what exactly does the congressman want? For the Federal Trade Commission to force the firms to extract all their buried fine print about how they might distribute your data, and broadcast it loud and clear. “I think if most people knew that this information could be sold to third parties they would think twice,” Schumer said. “The last gift any of us want to give away this holiday season is our most personal and sensitive information.”

While there’s no evidence that these companies have let anyone’s genetic data fall into the hands of hackers—or anything half that bad—their policies do grant them free rein to host, transfer, process, analyze, distribute, and communicate your genetic information. You still technically own your DNA, but they own the rights to what’s in it—after it’s been anonymized and de-identified, of course. Both companies say the primary way they use this genetic data is to improve their products and services. But both have research partnerships that involve exchanging data for money—23andMe with drug companies like Pfizer and Genentech, Ancestry with Alphabet longevity spinout Calico.

“This isn’t a videogame, it’s people’s genetic code and it’s a very valuable commodity,” says Peter Pitts, the president of the Center for Medicine in the Public Interest and former FDA associate commissioner. He’d like to see more transparency from Ancestry and 23andMe about how often they resell DNA data and how much they make from it. That’s the only way for people to know what it’s really worth. “To treat it like a toy and put it under the Christmas tree is incredibly irresponsible.”

But that’s exactly what millions of people are going to do. While Ancestry officials didn’t provide exact sales figures for this year’s Black Friday weekend, they did say they sold three times as many kits as the same time period in 2016, an amount they’d previously reported as 560,000. Going into the long weekend, the company had sold slightly more than 6 million tests since launching the product in 2012. 23andMe declined to give any financial details, but thanks in part to a big price cut, its health test was one of Amazon’s five best-selling items on Black Friday, behind the Amazon Echo Dot, two other Alexa add-ons, and a programmable pressure cooker.