This clinical case report illustrates the potential dilemmas that can arise from knowledge gained through genetic analysis. These conflicts require careful ethical analysis of presumed duties to protect patient privacy and maintain confidentiality, the duty to warn a second party of a health risk, and the duty of veracity. While the questions raised by genetic testing of one individual for disease that reveals potentially important information about relatives, such as risk for Huntington chorea or breast cancer, have been discussed, the (...) continuing expansion in our capacity for sophisticated genetic analysis continues to present new and challenging situations. The resolution of this case and others like it requires close collaboration among the treatment team, geneticists, and clinical ethicists. (shrink)