Just after a troubled rollout of President Obama’s takeover of the health-insurance market, the Food and Drug Administration (FDA) is being charged with attempting a takeover of the burgeoning field of personal genetic testing. That has been the erroneous reaction to a stern letter the FDA sent the genetic testing firm 23andMe on Nov. 22. Published on the FDA’s Web site, the letter orders the company to halt sales of its $99 send-away genetic testing kits.

The company seems to open the exciting new world of genetic medicine to anyone with a credit card and enough saliva to send back for testing. Once analyzed, the firm allows people to log into its Web site and see whether they have any genetic irregularities thought to be associated with a variety of diseases.

There should be no question that ordinary people have every right to know their genetic code, what it says about their ancestry and what it indicates about their predisposition to develop certain illnesses. They should be able to get that information without having to consult someone with a medical degree. At best, the information would encourage people to change bad behaviors, get needed tests and tailor drug regimens.

If testing and reporting is done improperly, though, it could lead to wild misunderstandings, unnecessary anxiety and excessive medical spending. Genetic testing should not become like the Wild West of the dietary supplement industry into which Americans pour billions annually even though quality varies massively and dubious claims go unchecked. That’s why it’s good that the FDA stepped in and appears determined to assure the integrity of the many new medical applications that personal genetic testing is poised to produce.

The agency wants to make sure that 23andMe’s testing is reasonably accurate and the results it provides customers contain enough of the right information for laypeople to understand and act on the findings. Just because a person has a gene associated with breast and ovarian cancer, for example, doesn’t mean she will definitely develop either disease. The agency’s letter indicates that 23andMe failed to provide enough evidence that its genetic testing, its analysis and its reporting are up to reasonable standards.

There’s a lot going on in genetic medicine that will result in breakthroughs new to doctors and other health-care experts. The most promising new tests are likely to be clinical, not mail-in. Researchers are tantalizingly close to matching anti-cancer therapies to particular tumors, tailoring doctors’ attack to the genetics of individual masses. Scientists once thought that most of the human genetic code was useless “junk DNA.” Now they are finding that the junk actually controls the circuitry of human cells, which creates a world of new medical understandings and treatments. Even as it slapped 23andMe, the FDA last month approved a new gene sequencer, another step in bringing down the cost and time associated with genetic analysis.

As the field advances, the government’s role is to continue funding basic scientific research and to provide a regulatory environment in which entrepreneurial companies will have the incentive to bring novel medical services of high quality directly to patients. Congress is going in the wrong direction on the first. The FDA, though, is so far doing a reasonable job on the second.