I have to confess to feeling more than a little trepidation at the prospect of interviewing Sheila Kitzinger. She is unequivocally the high priestess of natural childbirth, a household name whose numerous books are hungrily consumed by expectant parents. She has done more to change attitudes to childbirth in the past 40 years than anyone else, conducting a relentless crusade against the medicalisation of childbirth and the detrimental way in which the hands-on experience of midwives has been subjugated to the greater pathological experience of obstetrician.

I, meanwhile, earned the unenviable status of Public Enemy Number One in the eyes of the natural birth movement after writing an article earlier this year for this newspaper. In it I dared to put into print criticisms that countless parents feel once the reality of labour and new parenthood fails to match up to the natural birth ideal. I could barely believe the heated passion of some of the responses. Alongside phone calls and letters of support, I got hate mail, while the National Childbirth Trust (NCT) website appeared to talk of little else for months, with some members taking it very personally and demanding that I be sent on an NCT training course to be "put right". Now, I prepared to enter the laird of the queen bee herself, complete with birthing stools as coffee tables and batiks of birth symbols lining the walls. Would I emerge alive?

Kitzinger shot to prominence in 1962 with the publication of The Experience of Childbirth. The medicalisation of childbirth was at its peak in the late 1950s and Kitzinger's message - that birth was a powerful and exhilarating psychosocial, even sexual event where women needed to retain control - struck a chord with countless parents. There's no doubting her impact: as a result of her efforts, doctors now at least question the need for routine enemas, shaving and episiotomies and accept that the missionary position may not be the best one for giving birth.

But the flip side of this revolution has also been damaging. Childbirth is now more politicised than at any point in its history. Women are caught between two polarised stools of high-tech, medicalised birth and natural childbirth. Two surveys published in the past week alone illustrate the opposite ends of the debate. One based on a small sample found that babies born to mothers under the influence of Pethidine were at a slightly higher risk of becoming drug addicts as adults. The other found that mortality and morbidity rates for breech babies were reduced if they were delivered by caesarean section. The first seemed to strike a blow for natural childbirth, the second to push women further into the arms of the doctors.

Kitzinger, 71, is a likeable woman - funny, intelligent, warm and keenly alert and youthful. She is also that rare thing in the modern western world, a genuine feminist social revolutionary. "We are there, marching. You've got to change the system, you've got to change society, you need revolution!" she exhorts with a large laugh, her fists in the air. "For me, childbirth, preparation for childbirth and looking back on childbirth as well as making sense of it is to do with feminism, with women reclaiming their bodies." Revolutionaries can afford few regrets in case they should be deterred from their cause and Kitzinger admits to few. The drawbacks to her crusade are secondary to the aim of changing the culture in which women give birth. "It's not pleasant to have anything polarised, it can be nasty and upset relationships, but maybe we need to be uncomfortable, maybe that is how sparks are produced which compel new creative thinking."

She is a workaholic, a social anthropologist by training who loves nothing more than being out in the field with women in labour to learn from the experience. She struggled as a mother to marry her own career needs and aspirations with those of her five daughters. "I suppose there's a little bit of me that thinks, if I'd stayed home, prided myself on my apple pie and not argued so much then it might have been easier for some of the girls to have gone and done their own thing. But I don't think you can prepare girls for growing up for the world in which we live today, a world which needs to be changed, by simply seeing yourself in the mother role. I wanted to have warrior children."

Her passionate enthusiasm stems from her own experience of birth: five exhilarating, "enjoyable" labours without complications. "I remember thinking the first time I had a baby, now this is a sport I can do. In the first stage of labour it's a bit like swimming in very powerful waves, icy-cold water with pebbles being raked up and dashing at your body and bruising you, it's thrilling and you go with the waves." ("You think I'm a sado-masochist, don't you?" she said subsequently. "Are you?" I asked. She didn't reply, just smiled).

But the real seeds were sown by her mother, a midwife and active campaigner for birth control, who counselled women in her own sitting room with little Sheila hiding behind the sofa. Her mother clearly had a profound influence on her life. There were tears in her eyes as Kitzinger recalled how she had been with her on the day she died, some 20 years ago. "Mother was passionately concerned about different aspects of women's lives, but she left school when she was 14 and hadn't ever had the education to do the things she needed to do. I felt that I had the education and therefore it was my duty to take her work forward."

Kitzinger talks openly about the fact - a statistical curiosity even to her most ardent fans - that three of her five daughters are lesbians. She says she has never wondered why. "It may be very uncritical of me, people have questioned whether this may be a reaction to me and my work, that they've gone off and become lesbians in order to avoid childbirth but it all seems to make sense to me. My work dovetails absolutely with what my lesbian daughters are doing in the field of gender relationships, the right of women to decide on their own sexuality and express themselves openly."

But behind this wall of rather categoric certainty I detect more than a hint of vulnerable conciliation, acceptance even that there has been a certain amount of negative fallout from her work. She has been hurt by accusations from journalists who have blamed her for their own difficulties with childbirth and breastfeeding. "I pretend that it doesn't, but of course it hurts. I thoroughly enjoyed labour and everything I am doing and have always done in childbirth has to do with that joy. But I meet many women who have had terrible experiences, who are deeply traumatised by their birth experiences and I have to take that on board. I must confess that I find depression very difficult to cope with in anybody else because I've never been depressed."

Unlike many in the natural birth movement, she supports women who choose to have an elective caesarean and accepts that some women "feel deceived, cheated by their experience of birth. The NCT teachers would say we don't just teach for women who want drug-free births and that's true, but their whole raison d'etre is just that. The NCT says that women must be able to make informed choices and that's important, but I think we need to go a stage further and acknowledge the emotional pain and all the pressures that women are under. Childbirth has become a performance art and that's so sad because it is an intense living experience involving all our emotions."

Though she was a founder member of the NCT she fell out with the organisation for a time in the 70s when she published The Good Birth Guide. They decided that the book was causing harm, undermining the good relations with senior hospital staff that they had painfully built up over the years, and passed an overwhelming vote of no confidence in her. "It's silly really, but that still hurts."

Clearly she feels many of her ideals have been misrepresented.

"We've failed to see birth as something which is overwhelming and that relates to my image of the waves of the sea. This is not something you learn like you use a computer and have control over it and part of the glory of it is that you are overwhelmed just as you are when you are making love. Lots of people don't understand why I make the sexual analogy but when you're about to have an orgasm, you can't time it or say I'm going to breathe this way and it's going to be just right because I've practised, you go with it and you can't say no to it. It's the same with birth - certainly in the second stage of labour."

Birth may be safer now than it has ever been, but things can and do go wrong and that understandably raises anxiety levels in the mother and all those around her. It was one last passing comment from Kitzinger which made me wonder whether it may be this all-pervasive anxiety about labour that lies at the root of our need to control it, whether that be "naturally" at home in a water pool, or plugged into a monitor in hospital. "People feel the need to give advice because they're anxious. When I start dishing out advice it is usually because I'm not centred and it's usually dumb advice." I did a double-take - her books are full of advice. Is her need to control and inculcate better practise among new mothers actually born of an acute anxiety? Beneath that warrior revolutionary is there just another anxious, bossy, caring but controlling mother who asked me if I needed to go to the loo before I set off for home?

"I try not to say 'should' and I try to explore different things that women do in different circumstances and act as a channel for how women live their lives." So what advice would she give to all those women out there who feel they have failed to have the supremely enjoyable, quasi-sexual experience of childbirth that she is so openly exultant about? "They probably have been let down by what they perceived as 'natural' childbirth, we often tell women that they ought to take control of aspects of their lives in a way which makes them feel failures as soon as it's unsuccessful. What we omit to talk about is the social situation in which they found themselves. If a woman says that she feels she has failed, my first reaction would be to say that I understand that and then I would ask if she felt that there were others who had failed her, and then you can begin to deconstruct it, the pressures that exist on the midwife or obstetrician." The idea that it may be the very ethos of natural childbirth that has failed women does not enter the equation. On with the revolution!

• Rediscovering Birth by Sheila Kitzinger is published by Little Brown at £18.99. Life after Birth by Kate Figes is published by Penguin at £7.99