In a contribution to The Journal of Medicine and Philosophy, Professor Rosamond Rhodes argues that individuals sometimes have an obligation to know about their genetic disorders, because this is required by their status as autonomous persons. Her analysis, which is based on Kant's concept of autonomy and Aristotle's notion of friendship, is extended here to consequentialist concerns. These are of paramount importance if, as we believe and Professor Rhodes herself implies, the Kantian and Aristotelian doctrines can be helpful only in the sphere of private morality, not in the public realm. Better tools for assessing the right to genetic ignorance as an issue of public policy can, we contend, be found in Mill's ideas concerning liberty and the prevention of harm. Our own conclusion, based on the Millian way of thinking, is that individuals probably do have the right to remain in ignorance in the cases Professor Rhodes presents as examples of a duty to know.