This chapter discusses issues from the study of human sexuality that influence the development of normative and non-normative sexual behavior and are important in understanding and treatment of sexual offending behavior. Authors review sexual communication, including sexual consent, the impact of culture and society on sexuality, and what is known about sexual behavior and sexual attitudes. Additionally, important topics that are often encountered in treatment, supervision, and incarceration, including gender identity, sexual dysfunction, and compulsive sexual behavior are reviewed. The chapter presents available empirical data, as well as conceptual and theoretical understanding of the issues. Finally, where appropriate, interventions and treatments are provided.