The following seems a little bass-ackwards: FDA doesn't regulate companies that sell bullsh*t medicine - that is, "herbal supplements" which these highly profitable companies strongly imply can treat disease (and are sometimes unsafe, just like real pharmaceuticals.) But this same agency is now warning DNA testing companies that they're out of compliance, even for products that aren't intended to diagnose disease. I have two 23andMe kits sitting in my office right now that I haven't sent in yet, and I'm going to be pretty annoyed if FDA's ruling affects them. I suspect I'm not the only one. Following FDA submission rules is enormously expensive and time-consuming, and most of these companies don't have the resources to do it. Unless we think of a sensible solution, good-bye DNA testing industry.
This personal genomics/personalized medicine revolution everyone is talking about won't get her if it's made illegal. The problem is not that there should be no regulation, it's that there should be consistent, non-stupid regulation, and the U.S. is going to damage a domestic industry that will be very important in the near future early in its development.
[Added later: Alex Tabarrok at Marginal Revolution says it much more elegantly and directly: "The idea that the FDA can regulate and control what individuals may learn about their own bodies is deeply offensive and, in my view, plainly unconstitutional."]