Confidentiality is a cornerstone of the physician-patient relationship. Breaches of confidentiality in the context of genetic testing are of particular concern for a number of reasons. First, genetic testing reveals information not only about a particular patient, but also about his or her family members. Second,genetic testing can label healthy people as “at risk,” subjecting them to possible stigmatization or discrimination by third parties. Third, as genetic testing becomes more widespread and is incorporated into primary care, breaches of confidentiality might inadvertently occur more frequently because primary care providers may not be trained to understand the uniqueness of genetic information. Until now, genetic services have been provided primarily by medical geneticists and genetic counselors. However, with the proliferation of new genetic presymptomatic and carrier tests, primary care physicians are going to become increasingly involved in genetic testing. Currently, little is known about physicians’ attitudes (other than those of medical geneticists) toward disclosure of confidential genetic information to third parties.