"Relatively little of that information would be definitive," says Beverly Yashar, a professor at the University of Michigan and president of the American Board of Genetic Counseling. She says unlike clinical tests for a specific health problem, the tests that 23andMe provide are more general. "That technology is about susceptibility, odds ratios; it's not testing a specific gene. So you really have to think about how you deal with information and how comfortable you are with uncertainty when you have a risk."

Yashar and other genetic experts, while welcoming the increased public awareness of genetics that commercial tests have helped foster, raise many questions about the tests.

What do consumers do with the knowledge that they have some hard-to-quantify chance of developing a condition, or that they might pass some risk on to their children? Would a suggestion that an individual might have an increased risk for breast cancer cause that person to look into prophylactic surgery? Would genetic information on possible disease risk cause people to pursue healthier lifestyles, or could it create a sense of resignation that medical conditions such as diabetes are "destiny?" Questions also have arisen about privacy and employment.

The FDA steps in

These questions, coupled with concerns about the accuracy of the tests, have led the FDA to closely monitor companies such as 23andMe.

On Nov. 22, citing the company's lack of response to the agency's concerns, FDA Deputy Director Alberto Gutierrez instructed 23andMe to cease marketing its genetic testing kits. Within a few days, the company had stopped marketing the health-related features of the kits and redesigned its website to focus on the ancestry elements of the genetic tests without making any medical or health claims. 

"For customers who purchased a 23andMe kit on or after Nov. 22, 2013, analyzed health-related results will not be available. They will receive raw genetic data and full ancestry information," said Kendra Cassilo, a spokeswoman for the company. "The company (has) agreed to discontinue new consumer access to the health-related genetic reports while it completes the submission process for FDA marketing authorization."

The announcement created a flurry of comments and analysis from those following the direct-to-consumer genetics industry. Many were critical of 23andMe's foot-dragging when dealing with FDA requests, while others said the government agency was fighting a losing battle against increased consumer demand for personal medical information.

But some longtime observers say the market for DTC genetic tests is already contracting.

John Conley, a law professor at the University of North Carolina whose Genomics Law Report blog tracks the industry, notes that other DTC companies have been bought up by clinical organizations or have folded.

"23andMe appears to be the only surviving major player in the health-related DTC market. Although 23andMe claims almost half a million users, its results have fallen far short of initial optimistic expectations," he wrote in a Dec. 3 blog post.

Conley added that though he personally was rooting for 23andMe, "I'm extremely skeptical that this market has a future."

Conley also notes some legal problems for 23andMe, which was hit with a $5 million lawsuit in late November, one which specifically lists lack of FDA approval for the company's products in questioning the accuracy and validity of the tests. 

Regulators eyeing clinical genetics testing

A bigger issue for genetic testing may be recent FDA signals that it will more closely regulate tests conducted in a clinical setting, which it has not done to date.

Susan Laine, an FDA spokeswoman, says that the FDA has always had jurisdiction over any tests that are used to diagnose, treat or prevent a disease. She says that the FDA has generally not enforced regulations that apply to laboratory-developed tests (LDTs) used in hospitals and clinics, but that the agency is re-examining the issue.

"These tests have become more complex and high-risk and are playing an increasingly important role in clinical decision-making," Laine said. "As a result, LDTs that have not been properly validated put patients at risk, such as for missed diagnosis, wrong diagnosis, and failure to receive appropriate treatment. FDA believes that a risk-based approach to regulate these tests is appropriate, sought public feedback and is currently working on guidance that will outline our approach for regulation."

Yashar says the possibility of increased regulation does not bother her. "As a medical community, we want to make sure our patients have the highest quality of care, " she says. "There is a reason why we have regulation around all aspects of health care, and it would be nice to see that extend to genetic testing also."