William Masters, who died on February 16th aged 85, was one of the leading researchers in the field and marital satisfaction in the last 35 years than that other 1960s icon, the contraceptive pill.
The therapy programme they developed helped clients by providing sex information, alleviating anxiety about sexual performance and encouraging verbal, emotional and physical communication with their partners. Before this, any approach to sexual disorders had focused on the individual. Masters and Johnson included both partners in the therapy process, emphasising mutual responsibility for change and for finding a solution.
Born in Cleveland, William Masters became interested in the nature of sexuality while studying medicine in New York in the early 1940s. He joined the Washington University school of medicine in 1947, and began researching sexual functions in 1954. Three years later, Johnson joined him as his assistant.
Their investigation of the physical aspects of sexuality produced some of the first reliable data in the field, and widened public debate and awareness of the role of sex and sexuality in relationships.
Alfred Kinsey had begun that debate with Sexual Behaviour In The Human Male (1948) and Sexual Behaviour In The Human Female (1953), which, among other things, had disclosed the frequency of various sexual practices. They had caused a furore, with critics voicing the view that the study would undermine the family. William Masters believed that "science, by itself, has no moral dimension, but it does seek to establish truth, and upon this truth morality can be built" - and he and Johnson set out to find the truth. Their initial research, with 312 men and 382 women, was published as Human Sexual Response (1966), and remains the keystone of modern sex therapy. While Kinsey discovered how many people were doing what, Masters and Johnson explained what happened when they did it. Using polygraph-like instruments, laboratory observation and measurement of their research subjects while they were having intercourse or masturbating, the couple identified four phases in the human sexual response cycle - excitement, plateau, orgasm and resolution.
Although written for the medical community, Human Sexual Response became a bestseller, as did Masters and Johnson's next book, Human Sexual Inadequacy (1970), which was concerned with the treatment of impotence, premature ejaculation, lack of sexual desire and other sexual problems. In the wake of these two publications, the field of sex therapy - the clinical treatment of sexual problems - was born.
By 1964, Masters and Johnson had established the Reproductive Biology Research Foundation in St Louis. During this period, he and his first wife divorced and, in 1971, he married Johnson. Two years later they established the Masters and Johnson Institute, a clinic for the treatment of sexual problems.
They published The Pleasure Bond (1974), a fresh look at sexuality and commitment, and Homosexuality In Perspective (1979), which described the sexual responses of gay men and lesbians. They debunked the idea that homosexuality is a mental illness, but their claims to be able to change the sexual preferences of homosexuals met with considerable criticism from the gay community and other sex researchers. A further work, Human Sexuality, appeared in 1982.
The couple's later book, Crisis: Heterosexual Behaviour In The Age Of AIDS (1988), cowritten with Robert C. Kolodny, provoked another storm, this time from AIDS researchers and health workers who disputed their findings. The authors advanced the theory, now largely accepted, that engaging in risky sexual practices may be as important as membership of a high-risk group, such as drug users, in defining HIV risk, and also recommended safer sex practices for heterosexual, non-drug users.
Masters and Johnson worked together until 1992, and continued to collaborate, after their divorce the following year, on Heterosexuality, which was published in 1994, the year that Masters retired.
The expectation that sex should be a source of pleasure, personal development and empowerment for all is a legacy of the 20th century which Masters and Johnson were instrumental in developing. Their contribution on problems of sexual functioning and therapeutic interventions remains among the most significant work in these areas.
William Howell Masters: born 1915; died, February 2001