Virginia Johnson: Pioneer researcher who worked to erase taboos around human sexuality

Groundbreakers: Virginia Johnson Masters and William H Masters in 1972 (AP)

Virginia Johnson was the female half of the Masters and Johnson scientific research duo that in the late 1960s redefined sex as a quantifiable, perfectible pleasure of human life to be pursued without guilt or fear. She grew up on a Missouri farm, had no college degree and by the end of her career was nationally recognised as one of the most daring researchers of the postwar era.

Along with William Masters, her research partner and one-time husband, Johnson built on the groundbreaking work of Alfred Kinsey to erase the taboo surrounding human sexuality. Kinsey, the author of the Kinsey Report on sexual behaviour published in the late 1940s and early 1950s, had largely focused on personal accounts of sex for his work. Masters and Johnson took a different approach: they took sex into a laboratory setting, where it could be studied with scientific rigour.

Their findings, first published in 1966 in the best-selling book Human Sexual Response and later explored in volumes such as Human Sexual Inadequacy (1970), impressed academics and titillated a nation in the throes of the sexual revolution.

Of Masters and Johnson's early readers, the oldest were born in the Victorian age. The youngest came of age in the era of Marilyn Monroe. Those not scandalised by the duo's candid and technical discussion of masturbation, coitus and orgasms found a measure of comfort in the material. If the sexual act could be studied, then it could be improved, and problems such as impotence and frigidity could be cured like so many other afflictions of the human body.

In the mid-1950s, Masters was a gynaecologist working in St Louis at Washington University's medical school on a study of sex that ultimately would include 694 volunteers – 312 men and 382 women ranging in age from 18 to 89. Research instruments reportedly included a Plexiglas phallus equipped with a camera that could document orgasms experienced by a woman.

Masters instinctively understood that, to work, the project would need a woman with him at the helm. "My attitude was," Masters said, "that if you're going into sex research, it is apparent that both sexes should be represented."

So it was that in 1957 he hired Johnson, a former country singer and divorced mother of two who was looking for work while she studied sociology at Washington University.

At a time when many scientists did not consider sex a legitimate field of scientific inquiry, Masters risked his professional reputation to pursue the project. But by one interpretation, Johnson risked even more. Ladies of her generation had not been brought up to discuss – much less seek – sexual satisfaction. "I was never told about menstruation or anything," she once told Time magazine. "There was a very rigid rejection of anything sexual. You didn't talk about it."

Over time, she ascended from assistant to co-director of the Masters and Johnson Institute, as it became known. She was said to have brought a more inviting, welcoming manner that compensated for Masters' scientific bearing. She pushed for them to appear on television and in other mass-media outlets such as Playboy and Redbook magazines, decisions that helped to bring their work to an ever larger audience.

With Masters, Johnson helped dispel notions that today might seem quaint. Among them were misconceptions that the size of the male organ determined sexual prowess and that baldness was a marker of virility. The pair showed that, surprisingly to some, a woman's orgasm could last longer than a man's. They debunked the idea that the elderly were consigned to lives devoid of sexual satisfaction.

Besides outraged moralists, their detractors included critics who resented the fact that Human Sexual Response seemed to overlook the mystical nature of love. The book was read by some, Time magazine wrote, to "suggest that good sex, like golf, is a matter of technique." Johnson flatly denied that such was the intention.

In Human Sexual Inadequacy, she and Masters documented their treatment of hundreds of couples that struggled with dysfunction, including premature ejaculation and difficulty achieving climax. They reported a remarkably low 20 per cent failure rate – a figure that critics in the scientific community found it difficult or impossible to replicate.

But the Masters and Johnson brand had been forged. Their treatment of sexual dysfunction became, for a time, a dominant brand of sex therapy in America. The therapy included two weeks of intensive therapy and as many as five years of follow-up; about 70 per cent of the program, had come from her ideas. Johnson, Masters said, had learned "more than any other woman in the world about human sexual function".

Mary Virginia Eshelman was born in 1925, in Springfield, Missouri. "I grew up with the sense," she once told The Washington Post, "that accomplishment and talent were marvellous, but that marriage was the primary goal." She showed early promise as a singer, and she studied music, sociology and psychology. Her early jobs included stints as a radio country-music singer, a newspaper reporter covering business, and a market-research assistant for a CBS affiliate in Illinois.

Their later books included The Pleasure Bond (1974), written with Robert Levin, and Homosexuality in Perspective (1979). With Robert Kolodny, they wrote Masters and Johnson on Sex and Human Loving (1986). In 1988, also with Kolodny, they wrote Crisis: Heterosexual Behavior in the Age of Aids, which US Surgeon General C Everett Koop criticised as "irresponsible" for what he called its use of "scare tactics" in addressing the spread of Aids.

Johnson said the work of destigmatising sex would be long. "We'll need two generations," she once told an interviewer, "who grow up believing that sex is honourable and good for its own sake, and not something to be kept hidden away in a jewel box to be taken down for festival occasions on Friday and Saturday nights."

Emily Langer, The Washington Post

Mary Virginia Eshelman, sex researcher: born Springfield, Missouri 11 February 1925; married firstly George Johnson (one son, one daughter; marriage dissolved) 1971 William Masters (divorced 1993; deceased 2001); died St Louis, Missouri 24 July 2013.