Genetic testing for cancer susceptibility is an application of biotechnology that has the potential both to improve the psychosocial and physical wellbeing of the population and to cause significant psychosocia1 and physical harms. In spite of the uncertain value of genetic testing, it has captured the interest of biotechnology companies, researchers, health care providers, and the public. As more tests become feasible, pressure may increase to make the tests available and reimbursable. Both the benefits and harms of these tests lie not as much in the tests themselves, as in their power to predict or alter the future. The value of the tests does not derive from the information per se, but from the ability to communicate effectively the information to patients and providers, and the behavioral responses of patients, providers, and others to this information.