Advances in genetic technologies have led to the identification of hundreds of single that are associated with a variety of complex diseases, including cancer, diabetes, cardiovascular disease, and Alzheimer disease. Although personalized genomic tests that provide information regarding the risk of development of multiple diseases may be important tools in the near future, their use is not recommended outside of a clinical trial until these tests are validated as clinically useful in appropriately designed prospective studies.Testing for single-gene disorders should be approached in accordance with accepted guidelines that address the evaluation and management of these specific diseases.