IntroductionThe purpose of this evaluation was to compare parent and nurse use of an original children’s book about DNA function as a potential assent aid. We also appraised parental knowledge about DNA and use of genetic testing results. MethodWe used mixed qualitative and quantitative methods. Parent-child dyads were recruited at an urban pediatric hospital. Knowledge of genetic concepts was assessed in adults using the Genetic Knowledge Index. Participants read the book, What DNA Does, with a nurse or alone, and participated in interviews with investigators. Content of field notes from interviews were analyzed. ResultsParent and child knowledge of DNA and gene function was generally poor, but improved in most cases, particularly after reading with the nurse. DiscussionThe evaluated book is appropriate as a teaching aid in the child assent process in research or prior to genetic testing, but should be presented by clinicians in most cases.