Although adolescent sexual behavior has been of considerable interest to social scientists, most of the work in this area has been theoretically barren. This paper presents an outline of a conceptual model that incorporates a majority of the existing research on adolescent sexuality. Drawing upon principles from a macro-exchange framework, this model focuses upon the system of factors that affect adolescent females' transition to nonvirginity. Based upon the existing research, five major factors are presented: (a) Attractions Within the Family System, (b) Social Control Barrier, (c) Alternative Attractions, (d) Personal Readiness Characteristics, and (e) Social Milieu. It is proposed that the net effect of the interplay of these major spheres of influence results in a social-psychological condition of "transitional proneness" towards nonvirginity. General propositions and suggestions for future research are presented.