Introduction: Diverse sex development (dsd) is an umbrella term for different congenital conditions with incongruence of chromosomal, gonadal, and phenotypic sex characteristics. These are accompanied by various uncertainties concerning health-related, medical, psychosocial, and legal issues that raise controversial discussion. Aim: The aim of this exploratory study was to investigate 3 questions: What are the most controversial and disputed issues in the context of intersex/dsd? Which issues are associated with the biggest knowledge gaps? Which issues involve the greatest difficulty or uncertainty in decision-making? A further aim was to investigate whether the group of persons concerned, the parents of intersex children, and the group of experts in the field had differing views regarding these questions. Methods: A self-developed questionnaire was distributed among persons concerned, parents of children with intersex/dsd, and experts in the field. It contained open and multiple-choice questions. The answers from 29 participants were entered into data analysis. A mixed-method approach was applied. Quantitative data were analysed descriptively. Qualitative data were analysed according to the principles of qualitative content analysis. Main Outcome Measure: Participants answered questions on the most controversial and disputed issues, issues associated with the biggest knowledge gaps, and issues associated with the most difficulty or uncertainty in decision-making. Results: The findings indicate that controversial issues and uncertainties mainly revolve around surgical interventions but also around the question of how to adequately consider the consent of minors and how to deal with intersex in the family. Significant differences were found between persons concerned and parents vs academic experts in the field regarding the perceptions of procedure of diagnostic investigation and/or treatment in adulthood, on legal questions concerning marriage/registered civil partnerships, and on lack of psychosocial counseling close to place of residence. Conclusion: The necessity of irreversible gonadal and genital surgery in early childhood is still a matter of strong controversy. To ensure the improvement in well-being of intersex persons, including a sexual health perspective, the positive acceptance of bodily variance is an important prerequisite. Psychosocial support regarding one-time decisions as well as ongoing and changing issues of everyday life appears to be an important means in reaching overall quality of life. Lampalzer U, Briken P, Schweizer K. Dealing With Uncertainty and Lack of Knowledge in Diverse Sex Development: Controversies on Early Surgery and Questions of Consent-A Pilot Study. Sex Med 2020;8:472e489.