Researchers who work with children and adolescents are confronted with a special set of ethical issues regarding informed consent. Federal guidelines generally stipulate that minors cannot provide informed consent for participation in research. Instead parental or guardian permission must be obtained for a minor to participate in research. However the literature in developmental psychology has shown that adolescents are able to make meaningful decisions and advocates for youth have argued that researchers must respect the autonomy rights of children and adolescents. The present review examines the developmental literature on children and adolescents' capacities to make informed, voluntary, and rational decisions to participate in research. The purposes and benefits of assent are identified. Recommendations are offered on how to enhance and respect minors' developing autonomy while protecting them from risks of research.