Body: "Psychology of sex and sexual behavior" is the study of Sexology.
Why study "Psychology of sex and sexual behavior"? Understand basic biological mechanisms regulating sexual behavior and motivation, describe variations sexual orientation and gender identity, get a better sense of how emotional needs are tied into sexual needs, if at all.
Some questions in "Psychology of sex and sexual behavior" involve sexuality, gender identification, sexual orientation, fantasies.
A few notable experts of "Psychology of sex and sexual behavior" include Henry Havelock Ellis, Alfred C. Kinsey, Carol Queen, Kurt Freund, Beverly Whipple, Albert Moll.