Genetic testing allows individuals to submit a genetic sample to a company, which then analyzes the genes for known anomalies or other problems. The idea is that by having that information, you may be able to be more aware of potential health problems down the road. Or even stave them off before they become a problem by changing your behaviors, diet, and exercise regimen. Companies like 23andme and Navigenics provide genetic DNA testing reports that purportedly tell you your risk factors for getting not only certain medical conditions, but also mental disorders, like bipolar or attention deficit disorder.
This may work fine for some very well-defined health issues, like heart disease (although a recent government investigation into these companies’ abilities to provide even this information reliably suggests some problems). But it doesn’t work at all for any mental disorder.