Questions related to testing children for adult-onset genetic diseases include many variables that generate different answers among different families. These issues include the biological nature of specific genes, concern about what benefits or harms may accrue from testing children, possible psychosocial sequelae, and ethical and legal concerns about personal autonomy. The shift in the physician-patient relationship from professional beneficence to patient autonomy has established the patient, or parents, as the primary decision-makers in questions about treatment or testing options. The role of parents as decision-makers for their own minor children has been reinforced by four seminal holdings of the United States Supreme Court. Assertions about protecting the future autonomy of children are invalid because minor children are not autonomous. Their parents, on the other hand, have a right--and perhaps even a duty--to exercise their own vested autonomy in making decisions that they believe are in the best interests of their own families. Geneticists are urged to provide clear and complete counseling to parents who seek testing for their children, and then defer to the parents as the primary decision-makers for their own minor children.