“You can’t handle the truth!”

That’s the federal government’s latest message to Americans seeking to learn the content of their own DNA.

Recent advances in biotechnology have allowed private companies to offer affordable genetic testing directly to consumers, to help them determine their risks of developing problems such as diabetes, heart disease, and various forms of cancer. In response, the U.S. government has told these companies that their tests must be approved by FDA regulators before they can be sold because, in the government’s words, “consumers may make medical decisions in reliance on this information.

These restrictions thus represent a new level of government paternalism over the citizenry. In the name of “protecting” us, the government seeks to prevent willing consumers from learning medically useful information about their own bodies that could tell them which diseases they may develop — and help them make important treatment, prevention, and lifestyle decisions.

Ten years ago, Dr. Francis Collins and Dr. Craig Venter announced the first successful (independent) sequencings of the human genome. Since then, the cost of genetic sequencing has fallen dramatically in a biotechnology equivalent of Moore’s Law. Mapping the first human genome took years and cost $3 billion. Now it takes only 8 days and $10,000. Industry analysts predict that in three years, it will take only 15 minutes and a mere $1000 — comparable to many routine medical tests.

As prices have fallen, several companies had started offering direct-to-consumer genetic tests which would give customers partial information about their DNA.

In May 2010, San Diego-based Pathway Genomics struck a deal with Walgreens to sell test kits at 6,000 stores nationwide. Customers would spit into a small vial, then mail the sample back to the company for analysis. For $79, customers could learn how their bodies were “likely to respond to 10 substances, including caffeine, cholesterol-lowering drugs called statins, the blood thinner warfarin and the breast cancer drug tamoxifen.” For $249, customers could be tested for their risk for 23 conditions “including heart attack, high blood pressure, leukemia, lung cancer and multiple sclerosis.”

The FDA immediately warned Pathway to either show that it had FDA approval or “prove why it should be sold without the agency’s blessing.” Walgreens then suspended its plans. In June 2010, the FDA sent letters to five other personal genomics companies warning that their direct-to-consumer tests would also require FDA approval as “medical devices.” The FDA’s logic was because customers might base medical decisions on their test results, Americans’ access to these tests must be restricted until the government gave its approval — for our own good.

Esther Dyson, a director of one of the affected companies (23andMe.com), has described such government restrictions as “appallingly paternalistic.” Customers wish to learn their personal genetic information precisely because it may help them make important medical and lifestyle decisions.

For instance, scientist Seong-Jin Kim learned from his genetic test that he had a “tenfold increased risk of macular degeneration, the leading cause of blindness in people over age 60.” As a result, he is taking “high doses of antioxidants, which have been shown to slow progression of the disease, has regular eye exams, and avoids activities that tend to overexert the eyes.”

Genetic testing can reveal important information about how quickly an individual’s body metabolizes certain drugs, such as the widely used blood thinner Coumadin. Such genetic information could help doctors tailor a dosage individualized for each patient, potentially reducing the chances of undertreatment (with continued risk of developing blood clots) or overtreatment (with risk of internal bleeding). Similarly, the FDA has already issued a recommendation that patients of Asian descent be tested for a specific genetic variation before they take the anti-seizure medicine carbamazepine, because that genetic mutation could greatly increase their risk of certain serious side effects.

Of course, like any technology still in its infancy, consumer genetic testing is imperfect. Craig Venter and colleagues performed an interesting experiment where they sent duplicate saliva samples from five different individuals to two separate testing services to see how the results compared. They found that the companies reported essentially identical results with respect to the subjects’ raw genetic data, but did show some variations in how they interpreted their medical significance. Venter and colleagues then made several recommendations on how to improve the quality and consistency of such commercial tests — recommendations which notably did not call for increased government regulations.