Do-it-yourself genetic tests offer to reveal any number of genetic health risks for a price that ranges from a couple hundred dollars to more than $1000. Some companies even promise to use your genetic information to create personalized dietary supplements to prevent diseases. One company claimed it could use DNA analysis to predict which sports were the best match for children. As you might have guessed, an expert called it "complete garbage." The Government Accountability Office recently sampled 10 do-it-yourself genetic kits and reported that companies offered contradictory information and misleading results, and in some cases promised far more than they could deliver.
For example, GAO's donors often received disease risk predictions that varied across the four companies, indicating that identical DNA samples yield contradictory results. One donor was told that he was at below-average, average, and above-average risk for prostate cancer and hypertension. GAO's donors also received DNA-based disease predictions that conflicted with their actual medical conditions--one donor who had a pacemaker implanted 13 years ago to treat an irregular heartbeat was told that he was at decreased risk for developing such a condition.
The GAO referred all four of the companies it tested to the FDA and the FTC for "appropriate action."
You can read a summary of the GAO report (and listen to their undercover phone calls) at their website.