Her timing could not have been better. Disappointment with the sexual revolution of the 1960s had prompted a fever of intellectual excitement among women, with one big feminist book after another on the bestseller lists. Six years earlier Germaine Greer had told women they were female eunuchs; now here was another brilliant young woman explaining why.
Ever since Freud, women had been faking orgasms during coitus and worrying that there was something wrong with them. Even talking publicly about such things was taboo andstruggled to find a language which wasn't medical or embarrassing for the more than 3,000 women who agreed to fill in a detailed questionnaire about their sex lives.
When she published their responses in TheReport: A Nationwide Study of Female Sexuality, it revolutionised the way American women thought about their bodies. A year later, in 1977, the book came out in the UK and British women excitedly passed copies to their friends, spreading message that conventional sex placed unrealistic expectations on women.
The British edition also produced her first hostile review - a warning, althoughdid not know it (omega) at the time, of much worse to come. "In my idealism I thought I could connect with those who wanted to hear what I was saying," she says. "I was making the point that clitoral stimulation wasn't happening during coitus. That's why women 'have difficulty having orgasms' - they don't have difficulty when they stimulate themselves. Shouldn't we just rethink the idea of what sex is and what equality is? That's what I went around the country saying."
In the 1970s, talking about masturbation was still regarded as shocking, but it was central toargument. She wasn't attacking men but trying to educate both sexes about the biological facts behind sexual pleasure. But if her insistence on listening to women was innovative, her linking of sex and human rights - the idea that what happens during sex raises questions of equality and fairness - was revolutionary.
Her first bad review in this country opened up a line of attack that would later be taken up ferociously by the Christian right in the US, which chose to characterise her work as an attack on the family. These days, the notion that women learning how to achieve sexual pleasure might destroy relationships between men and women seems bizarre, but almost from the startwork alarmed considerable numbers of people.
If they found her ideas scary,herself confounded popular assumptions about feminists. She was clever, unassuming and beautiful, so much so that she was able to support herself as a graduate student at Columbia University in New York in the early 1970s through part-time modelling. beauty is disarming, possibly even terrifying, judging by the fury she arouses in her critics. Indeed it is hard to believe she is now 63, or that she came to prominence at a moment when cosmetics and attractive clothes were "anathema" to the women's movement, as she recalls in an essay in her new book, The Reader.
In the early years of the women's movement, feminists rejected patriarchal demands that they should make themselves as attractive as possible to men. This led to recriminations when some of the leading lights, including, started asking if wearing lipstick really was incompatible with being a feminist. Perhaps the most potent symbol of this rejection of beauty was friend, the late Andrea , a radical feminist cruelly mocked for her appearance. weight made her an easy target for misogynists, who have always tried to dismiss feminists as embittered man-haters, but challenged such stereotypes.
She is soft-spoken, her Missouri accent toned down by years of living in Europe. When we discuss anatomy, she patiently explains the similarities between the clitoris and penis, exploding theories about irreconcilable physical differences between men and women. "You could say the penis is a vertical vulva," she tells me, "or that the vulva is like a horizontal penis."
In retrospect, it isn't really surprising that with each successive book, including TheReport on Men and Male Sexuality (1981) and her most radical work, Women and Love: A Cultural Revolution in Progress (1987), the attacks became more vehement and personal. When they culminated in a Time magazine cover attacking her work, says she was "truly amazed". A dozen prominent American feminists, including , Gloria Steinem and Stephen Jay Gould, rallied to her defence, arguing that the Time cover was an attack on feminism, with singled out solely because she was the most visible feminist of her time.
This show of support "gave me a lot of confidence", says, but she nevertheless moved to Europe at the end of the 1980s; later, after her divorce from her German husband, she moved to Paris. I get the sense that she is as much European as American these days.
Her conversion to feminism happened almost by chance when she was sent to take part in a TV commercial for Olivetti typewriters. "They were teasing my hair into some ridiculous beehive thing," she recalls. "I said I thought I'd got this commercial because I could type well - and that's when I found out."had been chosen not for her typing skills but her looks; the company's new slogan was "the typewriter that's so smart she doesn't have to be".
"It made me into a feminist," says. "I read about a group of women picketing Olivetti and I joined them." Soon she started attending meetings of the New York chapter of the National Organisation of Women, founded by Betty Friedan, author of another groundbreaking feminist book, The Feminine Mystique. At one of the meetings, the topic for discussion was the female orgasm: did all women have them or none, and did it take place in the vagina or the clitoris?
"There was a lot of silence,"remembers, and someone suggested she look into the subject. That's when she discovered how little research had been done and the idea for The Report was born. Later, when the book was finished, she realised it said a lot about men and asked herself whether they too were victims of cultural assumptions. "Are men's human rights being ignored by telling them they have to get an erection every time?" she wanted to know. Such questions prompted The Report on Men, which was republished in an updated form last year.
continues to worry about the pressure on men to perform, arguing that recent medical inventions such as Viagra actually compound the problem. She still uses the questionnaire format she invented for the very first Report, even though it has been criticised as unscientific; this seems a little unfair when the pioneer in the field, Alfred Kinsey, actually based some of his general conclusions about male sexuality on interviews with inmates of American prisons.
Like any clever, successful woman,attracts envy and her looks may at times have been as much a hindrance as a help. In the end, though, she is controversial because of her ideas, which show no sign of drying up. On the contrary, she is once again challenging received opinion, arguing that far from being marginalised since 9/11, questions about the female body and sexuality are central to understanding the world's problems. She believes that religious extremism in the East and West can be seen in large part as a protest against the growing power of women.
"Wearing a garment to cover yourself completely is an attempt to prove you are pure sexually," she says. "But women who put themselves in this position can never be pure enough - you are constantly on trial."
Reactionary attitudes to women's bodies are one of many signals, she argues, that we need a new system of values, based on secular human rights. Three decades on, this feminist icon is as fearless and original as ever.
'TheReader: New and Selected Writings on Sex, Globalization, and Private Life' is published by Seven Stories Press