This chapter examines the arguments for and against predictive genetic testing of minors for late-onset disease for which there is no treatment or cure. Huntington disease (HD) is the most commonly inherited neurological disorder, with a prevalence ranging from 4.1 to 7.5 cases per 1,000,000 in Caucasians. It is inherited in an autosomal-dominant pattern such that each child of a parent affected with the disorder has a 50% chance of inheriting the HD mutation. In most studies, the effects of genetic testing for HD on psychological health have been assessed mainly in terms of depression and well-being. When other psychiatric symptoms are assessed, presymptomatic carriers complain more about sadness, low self-esteem, aggressive behavior, and compulsions than do non-carriers. Potential types of harm that might be caused by the genetic testing of a minor for late-onset conditions include the loss of future decision-making capacity and damage to the child's self-esteem.