From cancer to the common cold, almost every human malady has something to do with genes. In an effort to cash in on our growing understanding of the connection between genes and disease, more and more companies are marketing genetic testing kits directly to consumers, says a recent press release from Harvard Health Publications. Their promotional materials promise to guide you to a healthier life by predicting your unique risk for developing certain diseases. But buyer beware: while most scientists agree that personalized medicine is on the horizon, many doubt that it’s as close as the test kit makers would have you believe, reports the September 2010 issue of Harvard Women’s Health Watch.

In medical settings, genetic tests are used to identify variations that cause serious health conditions. These tests are usually reserved for people known to be at risk for a specific disease because it runs in their family. Clinicians can also use genetic testing to help them select more effective drug treatments.

Exactly how commercial genetic tests will help is up in the air. These tests are under scrutiny by the federal government, which is concerned that the companies are making unsupportable claims for the value of the tests in making health decisions.

If you’re considering ordering a test kit, keep in mind the following:

They are expensive. The cost can run to several hundred dollars or more, and it isn't covered by insurance.

Your report will be based on incomplete knowledge. Your risk for conditions like heart disease, diabetes, and cancer depends on complex interactions between genes and lifestyle factors. Researchers haven’t identified all the genes responsible for these conditions or determined how factors such as diet or exercise influence the expression of those genes.

Genetically individualized medicine will come into its own when the predictive power of the tests improves and the cost falls. That day has not yet arrived, and there is no direct evidence that these tests offer any practical benefits, notes Harvard Women’s Health Watch.

Read the full-length article: “Direct-to-consumer genetic testing kits”