The progress of genetic knowledge magnifies existing ethical problems in medical genetics. Among the most troubling types of problems -- for medicine, patients, and the larger society -- are those of privacy and disclosure. Examples of the range of problems involving privacy and disclosure are: 1) disclosure of false paternity to an unsuspecting husband; 2) disclosure of a patient's genetic make-up to his or her unknowing spouse; 3) disclosure of information, against a patient's wishes, to relatives at genetic risk; 4) disclosure of ambiguous test results; 5) disclosure of adventitious nonmedical information, e.g., fetal sex; and 6) disclosure to institutional third parties, such as employers and insurers....