The discovery of major cancer susceptibility genes is likely to create strong pressures for clinical testing from biotechnology companies, insurance carriers, the medical community, and the public. However, before genetic testing for cancer predisposition is made widely available, we must identify the optimum strategies to enhance informed decision making, minimize adverse psychologic consequences, and promote adherence to recommended surveillance. This report provides an overview of behavioral research in these areas and, on the basis of this literature, presents suggestions for developing effective and ethical genetic testing protocols.