After years of collecting DNA information from millions of customers, 23andMe has an ever-growing trove of data it can use to create new products.

During a panel at SXSW on Sunday, the company is unveiling its latest: an individualized health report that gives customers a percentage likelihood they'll develop type 2 diabetes in their lifetime. And this product comes at zero cost to customers.

According to the CDC, one in three Americans has prediabetes, which means blood-sugar levels are elevated but not yet high enough to be considered diabetes. Ninety percent of those with prediabetes don't know they have it. 

Changes in lifestyle--like exercising more or eating healthier--can delay or prevent the onset of diabetes, which is why 23andMe thinks the info will be useful to customers. On its website, the company will let users input personal metrics, such as the number of times per week they exercise or eat fast food, and toggle them to see how they affect their likelihood of developing the disease.

Emily Drabant Conley, the company's VP of business development, told Inc. she believes this is the first direct-to-consumer genetic risk test for type 2 diabetes. 

It's the latest in a series of personal health reports the company has rolled out over the past two years as the company positions itself as more of a health company than an ancestry company. Last year, the company unveiled the first FDA-approved direct-to-consumer risk test for cancer. It previously developed similar genetic tests for diseases like Alzheimer's and Parkinson's.

After launching in 2007, the company became known primarily for its ability to estimate users' ethnic makeup based on their DNA. Today, customers can pay $99 for the ancestry test and another $100 for the health test, which provides info about genetic predispositions toward things like high cholesterol or cystic fibrosis.

The company's business model is interesting: Each time 23andme develops a new health report, existing customers can view their personalized results for free. 

"It's something we've debated a lot internally over the years: Should we charge, should we not?" says Drabant Conley. "Where we always keep landing is that it's really valuable to have an engaging product."

Customers who log back in to 23andMe's site are presented with a seeming infinite supply of optional survey questions on everything from sleep patterns to smoking habits to family health history. That information is immensely valuable to the company--it helps 23andMe build a massive data trove it can use to connect genetic variables in ways no company or research body has done before. The company is constantly adding new areas of research, so giving customers a reason to occasionally sign in again is important.

"When they come back to the 23andMe site, those customers might decide to answer some research questions," Drabant Conley says. "At this point in the business, that is more valuable than the potential incremental revenue we could get by charging for each report."

Last year, 23andMe received a $300 million investment from pharma giant GlaxoSmithKline​. The British company now has access to 23andMe's health data to help it develop drugs. 

23andMe is also working on its own internal drug development--the company's therapeutics team is at 70 people and growing.

For the diabetes test, the company used data compiled over several years from 2.5 million customers who had provided their type 2 diabetes status. In analyzing that data, the company found more than 1,000 genetic markers related to diabetes. The company then built a statistical model through which it can run each individual's DNA to determine their likelihood of developing the disease. 

More than eight million people have used 23andMe's service since its launch.

Unlike with some of its previous reports, the company didn't need FDA approval to be able to tell people their likelihood of developing diabetes. That distinction is related to the seriousness of the disease: While finding out one has a genetic predisposition toward breast cancer might prompt serious intervention, like a masectomy--which some customers have had after learning of their 23andMe results--the suggested course of action for a proclivity toward diabetes is less extreme, like losing weight or working out more.

The company fought a very public battle with the FDA for years over whether it had the right to provide certain health information to customers. CEO Anne Wojcicki told Inc. the company now complies with the government agency when necessary before launching to the public. 

Even so, some critics worry about the idea of handing potentially impactful health reports directly to consumers. "It's kind of circumventing a genetic counselor," Glen Cohen, professor of health law and bioethics at Harvard Law School, previously told Inc. "If we can democratize and expand testing, that's great. But there's this question as to whether this is the best way of doing it."

For its part, 23andMe presents each set of results with a disclaimer that it is not a diagnosis, as well as a recommendation to consult with a professional before making lifestyle changes.

Eventually, the goal for 23andMe is to be able to better understand psychiatric conditions like depression--what causes them, how they're likely to manifest, and what can help alleviate them.

"These are really complicated conditions and really the way I think we're going to solve them is with big data," Drabant Conley says. "That was the hypothesis in 2006, and we're seeing these things pay off, but there's still a long way to go."