As a result of the increasing effectiveness of cancer screening and preventive interventions, ethical issues, as well as legal liabilities, are increasingly associated with cancer genetic testing. These issues include the possible "duty to warn" relatives of inherited cancer risk, the appropriateness of testing of children and embryos, equity of access to genetics services, and potential harms of testing including the risk of genetic discrimination. An approach to these and other ethical challenges will be presented, drawing not only on recent case law but also on a broader bioethical framework.