The research team of obstetrician and gynecologist William Masters (1915—) and his then-wife, psychologist and sex therapist Virginia Johnson (1925—) pioneered the study of human sexual response. Their research helped to debunk myths concerning male and female sexual performance, to redefine society's definition of "normal" sexual behavior, to change both male and female expectations for sexual performance and sexual satisfaction, to encourage development of the sex therapy profession, and to coin much of the descriptive language used in modern discussions of sex behavior and sexual response. They also pioneered the use of direct observation as a research technique for the study of sexual behavior.

Masters and Johnson's discoveries led to numerous changes in sexual attitudes and sexual behavior. For example, Masters and Johnson's research focused attention on vaginal lubrications as a source of pleasure in intercourse and oral-genital activity, identified the source of that lubrication, and...