Sexology, a discipline that has evolved over the past 150 years, refers to the scientific study of sexuality. Academically, sexology spans the physical, biological, psychological/behavioral, and social sciences and typically includes the study of human sexual attitudes, interests, behaviors, development, problems, and aberrations. Today, sexology enjoys a position of respect in higher education in most nations – represented by academic departments, faculty appointments, majors and minors, undergraduate and graduate degrees, congresses, and a host of journals. In this entry, we present a brief history of sexology as well as select topics of interest, including psychosexual development, sexual and gender identity, sexual health, sexual respon...