In life-threatening situations, whether and under what conditions a minor should be allowed to refuse a lifesaving intervention is an important question. This article addresses the issue of whether adolescents, as a rule, possess capacity of sufficient quality that it should be respected even in the case of life-altering medical decisions. After reviewing the traditional approach to determining when adolescents should have their decisions respected, an approach that focuses on establishing capacity under a traditional informed consent model, the article reviews our evolving understanding of adolescent brain development and explores the implications for adolescent decision-making capacity. The author argues that a demonstration of understanding and mature reasoning abilities is not sufficient to establish decision-making capacity and that most minors do not possess fully mature decision-making capacity. Finally, the author suggests an approach to adolescent decision-making that is more reflective of the developing state of the adolescent brain.