The Food and Drug Administration has ordered a halt to sales of the Personal Genome Service (PGS) kit offered by the startup 23andMe. If you spit into a tube and send it along with $99, 23andMe provides you with information "on 240+ health conditions and traits" in your genetic code.

The FDA believes that the PGS constitutes a "medical device," making it subject to FDA regulation. And it argues that the product poses health risks. For example, "if the BRCA-related risk assessment for breast or ovarian cancer reports a false positive, it could lead a patient to undergo prophylactic surgery, chemoprevention, intensive screening, or other morbidity-inducing actions," the FDA wrote in a Nov. 22 letter.

If the PGS is inaccurate, or if 23andMe makes misleading claims about its capabilities, that would be legitimate grounds for regulation. But the FDA seems to be making a stronger, and much more dubious, claim: that even an accurate genetic test is dangerous because its results could be misinterpreted by patients.

The FDA's own example shows how weak this argument is. Obviously, it would be terrible if a woman got a false positive for a breast cancer gene and got an unnecessary mastectomy or chemotherapy as a result. But mastectomies and chemotherapy are not available over the counter. To get them, patients have to seek treatment from licensed physicians. If 23andMe's BRCA test is unreliable, doctors will be aware of this fact, order a more reliable test and help the patient to properly interpret it.

The point is a general one: Having more information about your health status is never dangerous by itself. It only becomes dangerous if patients use it to make dangerous medical decisions. But most dangerous medical decisions can't be made unilaterally; they generally require the assistance of licensed medical professionals who will do their own assessment of the situation before performing procedures that could harm patients.

More to the point, patients have a right to make dumb decisions if they want to. We don't ban patients from reading medical textbooks or WebMD, even though doing so undoubtedly leads to some harmful self-diagnoses. In a free society, patients have a right to accurate information about their health, even if medical professionals and regulators fear patients will misuse it. That includes information about our genetic code.