Distinctively and qualitatively different YSV and YPSV are more dangerous, manifest higher levels of coercion, or are predatory sexually violent toward strangers or casual acquaintances. There is a call for comprehensive, developmentally appropriate assessment tools sensitive to the unique needs of all types of sexually abusive youth, including YSV and YPSV. Discussed is the innovative risk assessment tool, Multiplex Empirically Guided Inventory of Ecological Aggregates for Assessing Sexually Abusive Children and Adolescents (MEGA) which incorporates the unique factors that need to be considered when assessing YSV and YPSV. The accumulated research findings on sexually abusive youth demand a new model and evidence-based standard that is vigorous, developmentally sensitive, and applicable to male and female youth of all ages and developmental abilities. Sexually abusive youth, in this article, is meant to be an encompassing and comprehensive term that captures the wide heterogeneity of a particular segment of the population of youth age 19 years and under who engage in behaviors that are sexually abusive or involve coarse sexual improprieties. New classification is presented identifying two subsets of sexually abusive youth currently not defined in the literature or in existing models or risk assessment tools: YSV and YPSV. References