Project Summary The birth of a child with ambiguous genitalia challenges societal beliefs about gender and ?normalcy?, and is both traumatizing and isolating for their parents and families. Parents are involved in making important medical decisions early in the child's life that can have long-lasting effects on the child's physical and emotional well- being. However, during the time of making these decisions parents are often affected by their own psychological distress and uncertainty about the child's diagnosis, which can potentially lead to hasty decision-making and poor long-term outcomes. The proposed project will utilize a mixed-methods research design, combining qualitative and quantitative research methods to ultimately develop an internet-delivered intervention to reduce uncertainty for parents of children with a Disorder of Sex Development (DSD). The study is guided by two aims: First, we will conduct qualitative interviews with parents of children with a DSD in order to better understand the aspects of the child's diagnosis, treatment, and prognosis that were previously and are currently triggering and maintaining elevated levels of uncertainty. Notably, we have an established consortium of 10 hospitals, all with specialized multi-disciplinary teams for the treatment of DSD, who are committed to participating in this study. As such, we will be able to obtain information from a wide range of parents in terms of race, ethnicity, and socioeconomic status. Second, we will analyze the qualitative data using thematic analyses and will use this information to develop a brief, 6-module internet-delivered intervention targeting the reduction of uncertainty. We will pilot-test this intervention with parents of children who have a new DSD diagnosis through any of the hospitals in our consortium, such that these parents will be participating in the study while going through the process of making these early medical decisions. We expect that parents who participate in the intervention will report lower levels of uncertainty and less psychological distress surrounding their child's diagnosis, which will allow them to make the best-informed medical decisions regarding their child's care, and ultimately result in better long-term outcomes for patients with DSD. The results of the proposed study will be used to develop a future, multisite, randomized controlled trial of the intervention.