Decision making in pediatric oncology can look different to the ethicist and the clinician. Popular ethical theories argue that clinicians should not make decisions for patients, but rather provide information so that patients can make their own decisions. However, this theory does not always reflect clinical reality. We present a new model of decision making that reconciles this apparent discrepancy. We first distinguish decisional priority from decisional authority. The person (parent, child, or clinician) who first identifies a preferred choice exercises decisional priority. In contrast, decisional authority is a nondelegable parental right and duty, in which a mature child may join. This distinction enables us to analyze decisional priority without diminishing parental authority. This model analyzes decisions according to two continuous underlying characteristics. One dominant characteristic is the likelihood of cure. Because cure, when possible, is the ultimate goal, the clinician is in a better position to assume decisional priority when a child probably can be cured. The second characteristic is whether there is more than one reasonable treatment option. The interaction of these two complex continual results in distinctive types of decisional situations. This model explains why clinicians sometimes justifiably assume decisional priority when there is one best medical choice. It also suggests that clinicians should particularly encourage parents (and children, when appropriate) to assume decisional priority when there are two or more clinically reasonable choices. In this circumstance, the family, with its deeper understanding of the child's nature and preferences, is better positioned to take the lead.