When Naomi Wolf gave birth for the first time, nothing happened the way she thought it would. She arrived at the hospital at 3am, when an angry nurse sent her into the toilet to stimulate her nipples - supposed to encourage stronger contractions. Within minutes, the nurse pronounced that her cervix had not dilated enough and the baby was in distress. She was rushed to a delivery room. Hooked up to a foetal monitor, she was forced to lie on her side. Drugs were dripped into her veins to increase dilation. She was offered an epidural and, in pain, took it: her partner was not allowed to hold her, yet she was told that if she flinched while the six-inch needle was pushed into her spine, she would be paralysed for life. Everybody watched only the foetal monitor, not her. She could not feel her legs. She was told that if she didn't deliver in 24 hours, they would operate; she was terrified and her labour stopped. The surgeon cut her open; she retched as she felt a violent, numb tugging. A baby was lifted out; Wolf lay naked and freezing. She heard the surgeon say, "I need to get this small intestine back in." With her abdomen still split open, she was unable to hold her child. She saw the reflection of the closing-up operation in the glass doors opposite. She saw a group of people, up to their elbows in her body, "an open cauldron of blood".

This was no scandalous one-off; as Wolf was to discover, it was an "ordinary bad birth", suffered by millions of American and, increasingly, British women every year. But it had a revolutionary effect on this mother. Naomi Wolf, author of the bestselling feminist book The Beauty Myth, importer of American-style power feminism, controversial adviser to Al Gore, white wedding dress-wearer, the radical feminist who looks like a beauty queen, "the sunny, shiny face of feminism": when she gave birth, things got ugly. "Pregnancy, birth and motherhood," she says, unequivocally, "have made me a more radical feminist than I have ever been."

We meet at Woodhull, a women's retreat in upstate New York. Today, she looks like an ordinary weekending mother-of-two: her usually voluminous hair is tied up, she wears black shorts, sandals, a maroon vest that doesn't quite hide a slipping pink satin bra strap. Her eyes are the colour of her sapphire engagement ring. Her voice is silky, but she is furious. "I feel absolutely staggered by what I discovered after giving birth," she says. "Birth today is like agribusiness. It's like a chicken plant: they go in, they go out."

The scandal of the medicalisation of birth is not new; from the 1960s, activists such as Ina May Gaskin and Sheila Kitzinger have fought against the interventionist tide that sees birth as an illness, rather than part of a woman's "wellness cycle". But it is a scandal that has reached extraordinary proportions: in 30 years, the Caesarean rate in Britain has more than trebled; one baby in five is now delivered this way. (The US figure varies from 50% for healthy, middle-class women in their 30s and 40s in private hospitals, to between 1% and 15% for those in public hospitals.) Of course, Britain is different from America in that the market does not rule healthcare - US hospitals get a $1,000 bonus for every epidural requested. But the story is absolutely relevant here, with doctors under increasing pressure to avoid litigation, a severe shortage of midwives, the increasing popularity of elective Caesareans for women who are constantly told that vaginal childbirth is traumatic and terrible, and the threats of private interests entering the health service.

It is not only birth that has shocked and radicalised Wolf: it is pregnancy and motherhood, too. She claims that throughout her pregnancy she faced "the medical establishment's sheer contempt for women's right to know", and was given misinformation, conflicting information or little information at all. Men would comment on how big she'd got. ("Nice to see you," said one, "...so much of you.") She, meanwhile, was mourning the loss of the independent, free-spirited young woman she had been; and realising, as so many women do, that "true revolution" would come about only when society had restructured itself "radically to support babies and new parents". In other words, the world was a liberated place for young women - until they had children, when all of that changed.

After birth, she suffered a crippling depression, which she tried to escape by walking, compulsively, around the streets at night. She noticed, very soon, that the expectations of her generation were not going to be fulfilled: high hopes of combining work and home, both partners working flexibly and sharing the childcare. She was acutely aware of a "radical social demotion" and a sense of "statelessness", made stark by the lack of value she felt was attached to the work of parenting. And all around she saw the egalitarian relationships of her peers collapsing into stereotypical gender roles, difficulties and rows. As she says, her politics had rebalanced around her belly.

Naomi Wolf is now 38, author of four books, mother of two children. She grew up in an "egalitarian paradise" in the hippy Haight-Ashbury district of San Francisco, with liberal parents ("My mother was reading The Second Sex in the delivery room," she has said). Her father was an English professor, her mother a graduate student; she has an older brother, half-sister and half-brother, the common thread being their father.

Much of what we know about her life we know from her books. At school, she had anorexia; as she wrote in The Beauty Myth (1990), "My choices grew smaller and smaller. Beef bouillon or hot water with lemon? The bouillon had 20 - I'd take the water. The lemon had four; I could live without it. Just." Her doctor said he could feel her spine through her stomach. The book - which was written, curiously enough, in Nicolsons Restaurant, the same Edinburgh cafe in which JK Rowling wrote the first Harry Potter - was a massive bestseller around the world, "the most important feminist publication since The Female Eunuch", according to Germaine Greer. Wolf was accused of being derivative because many of the ideas had been rehearsed before; but the accessibility of this powerful polemic undoubtedly brought to a new, younger generation feminist ideas about how "images of female beauty [are used] as a political weapon against women's advancement". Wolf was also accused of hypocrisy, for being the "anti-beauty cutie" who criticised the beauty myth while employing its tools. (If she had been plain, she said, that would have been used to attack her, too.)

Her childhood was studious but, post-anorexia, she was a lively Californian teenager - after a variety of boyfriends, including one who hit her, she lost her virginity at 15. As she wrote in her 1997 book Promiscuities, "Martin and I could have been a poster couple for the liberal ideal of responsible teen sexuality - and, paradoxically, this was reflected in the lack of drama and meaning that I felt in crossing that threshold." Wolf won a scholarship to Yale to study English literature; a Rhodes scholarship at Oxford; and then she moved to Edinburgh to live with a boyfriend, published The Beauty Myth and became a sensation.

Her books have always reflected her life; her second work, 1993's Fire With Fire, took on the subject of female power just as she was realising that she had some herself. It looked at why women became alienated from feminism in the 1980s, criticised its tendency to glorify victimhood and poked gentle fun at the right-on excesses of some kinds of American campus feminism (at one of her lectures, a student asked her whether the very act of writing a book was itself exclusionary to women who couldn't read). Her alternative was a glossy, can-do brand of "power feminism", of pay rises, achievements and kicking ass.

She got married in 1990 to David Shipley, an "egalitarian, nurturing man" who used to work for Bill Clinton and is now deputy national editor of the New York Times. As she wrote in Promiscuities, she wore a white wedding dress, and said it was a way of women returning once more to the times when we were "queens of our sexuality... When we are swaddled in the white satin of the formal bridal gown, we take on for a few rare moments a lost sexual regalness." All of this caused controversy, and consternation - even if she thought these things, was it politic to say so? But the biggest bomb was, undoubtedly, an article about abortion, Our Bodies, Our Souls, published in the New Republic in 1995. A pro-choice campaigner, Wolf wrote: "Clinging to a rhetoric about abortion in which there is no life and no death, we entangle our beliefs in a series of self-delusions, fibs and evasions . . . we stand in jeopardy of losing what can only be called our souls." Wolf claims she was trying to show that, even though abortion must be a "legal right", individual women (herself included) may still have moral or emotional difficulties with it. And that, at its best, feminism must always be "faithful to the truth".

It caused a furore - critics rounded on her for her semi-religious language (our souls, the furies) and for threatening abortion rights - and it appeared to give succour to the enemies of feminism. The Daily Mail trumpeted: "How pregnancy turned a feminist against the sisters." This makes her angry: "I'd like to say to the Daily Mail that it made me more radical than ever." So that's down to Rosa, six, and Joey, 20 months.

"I think that America and Britain hold mothers in contempt ," she says, expanding on her theme that it's not just women's bodies that are under attack, it's women's lives. "I think there is lip service paid about how important motherhood is, but the actual labour of mothering is seen as next to cleaning restaurants. It's underpaid, undervalued, disrespected. Just look at a playground. What do playgrounds say to women? They say - 'you know what, just fuck you! You haven't anywhere to change dirty diapers - fuck you, deal with it. You and your babies don't count enough for us to put in the plumbing. Are you going to sit for hours under the boiling sun? Okay! Because you don't count. This work doesn't count.' It's not even the physical discomfort that matters - it's the slap in the face about the status of the work you're doing."

In the book, Wolf lays out a "mothers' manifesto" - ranging from flexi-time for mothers and fathers to turning playgrounds into "true community centres" and founding neighbourhood "toy banks". There needs to be a radical mothers' movement, she says. "Politicians feel very comfortable using mothers and children rhetorically and strategically, without actually having to answer to representatives of mothers sitting at the table."

So why don't they have a political voice? "Well, the first answer is that we're exhausted!" she laughs. "But second, the most powerful interests are stacked against us. For instance, when motherhood is cast as your private problem, and the work/family conflict is seen as your lifestyle issue, and if you can't balance it, there's something wrong with you as superwoman - then that's very handy for the business lobby, which is hand-in-glove with the Blair government in your country and the Bush administration in mine."

In a brilliant section in the book, Wolf shows how "Machine Mom" - the "ideal of the superfunctional mother/worker, who is able to work at top capacity up to the due date, takes one to three months off to deliver, nurture and bond, finds top-notch childcare, and returns to work" - is nothing more than a product of the market. "Who are the beneficiaries of Machine Mom?" she asks. "Not women, not kids."

The third reason for mothers' lack of a political voice is ideological: "If motherhood is defined as that which gives and gives and never says, 'Help me with this', then you're a bad mom for saying, 'Yo, salary!'

"I think women should have it all, and so should men," she says. But the phrase shouldn't mean what it has come to mean. "'Having it all', as it is defined now, means working full-time and having a family - someone's going to pay the price somewhere. I think we need to evolve as a society in which men and women have balanced lives as workers, partners and parents, and a real community life. This is the big no-brainer conclusion at the beginning of the 21st century: that if you give it all to the marketplace, people become cogs in the wheel and everyone suffers."

In the US in particular, there is a shocking level of institutionalised discrimination against mothers who want to work: the only maternity leave is unpaid, just 12 weeks - "and even that was a 12-year struggle. Bush Sr said that if you had this, capitalism would collapse. It was one of the first things Clinton introduced in 1992." Britain's maternity policies are, she says, "right in the middle. They're worse than Norway, Denmark, Sweden, Italy; better than Greece, Spain. In Germany, they have three years, but it's not gender-equal. I don't support laws that say women get time off and not men, because that designates them as the caretakers." As examples of good policy, she points to China, where both parents get six months and can choose how to allocate it, and Canada - over 90% of pay for more than a year.

Much of Wolf's analysis is a criticism of the market's role in medicine; the corrosive effect of a free-market economy on something as fundamental and necessary as healthcare. It has resonances with other recent books by feminists, such as Stiffed by Susan Faludi and No Logo by Naomi Klein, which have looked back to the anti-consumerist roots of feminism with the view that an out-of-control market harms all ordinary people, and women the most. Has Wolf turned against the market? "Well, no, I believe in equipping women so that they're not disempowered in the market economy, and I do believe that social democracy is the best system," she says."In this book I'm using Marxist tools to analyse social organisation: looking at who profits, whose incomes would be jeopardised by change. But that doesn't mean I'm a Marxist, because I'm not."

She certainly isn't - there was a media frenzy 18 months ago when Time magazine revealed that Wolf had been paid $15,000 a month to advise the Democratic presidential candidate Al Gore. The magazine claimed that Wolf was telling Gore he should escape his "beta-male caste" and adopt a "reassuring wardrobe palette in order to heighten his attractiveness to women" by wearing "earth tones", greens and browns. The story was leapt upon by everyone from talkshow comedian Jay Leno to Vanity Fair magazine, which labelled Wolf "the Lady Macbeth of this drama" (the Clinton/Gore relationship). "Most of what was reported was an urban myth, complete fabrication," says Wolf now. So where did it come from? "The Republican National Committee, of course! I did make one of the remarks, which was taken out of context. I made the point, which was not rocket science, that a presidential candidate has to roll out a vision, whereas a vice-president has to support the president. I used the journalistic shorthand of these two roles as alpha and beta males - it was a kind of joke." Wolf was, in fact, an adviser to Gore on women's issues.

This was not her first encounter with Democratic politics - Wolf had previously worked for Clinton strategist Dick Morris, who was caught with a prostitute in the 1996 campaign and had to resign. "We don't need to go after people for their personal lives, just for their ideas," she says. "People have weaknesses, people have failings. I don't think it's anybody's business." For Clinton, too? "No. Absolutely not. I'm proud to say that I was one of the first feminists to take a line against 'our guy' - because it was a workplace issue. Meritocracy is so important, and if you're rewarding your staff on the basis of sexual favouritism, that is corrupting." It was quite a turnaround for the woman who, in 1993, had declared, "I am a Clintonite feminist." "The Clinton administration was exciting at the beginning," she says now. "Finally, some of the things we cared about were being addressed."

So, then, why did Gore lose? "You mean, why did he win so narrowly that he lost?" she laughs. "I think he had a very tough job running in an environment that was about being mediagenic - and he's a guy who's full of stature, full of great ideas, who's not particularly mediagenic. He was running after the most mediagenic president since Kennedy, and against someone who is as shallow and callow and devoid of ideas and depth as you can imagine, but who actually plays well on television, and plays to American sentimentality."

But Gore was, Wolf says, good on women. (No wonder - she advised him.) "I believe his agenda for women was a really historic agenda. I was honoured to bring the concerns of women to Gore's table, I'm sorry that he didn't win and the controversy was worth it for me." Much of the controversy focused on those earnings. "I make no apologies for my salary," she says. "I am absolutely entitled to it as a professional. The reporters should have done some work to find out what men at my level in that campaign were paid. Because, guess what? Hello! They were paid more !"

Why, then, was Wolf the only one, among all Gore's advisers, who was picked on? "Oh, that's too easy," she says. "Any woman who is a visible feminist gets criticised. Gloria Steinem faced 10 times worse than I did. I take responsibility for the fact that I take strong positions and go after vested interests, so fair enough."

This tendency to take responsibility for what she provokes in others is an unusual trait and a powerful one, which has the effect of stalling her attackers. For example, the writer Camille Paglia once called Wolf "the Dan Quayle of feminism - a pretty airhead who has gotten any profile whatsoever because of her hair"; she called her "a Seventeen magazine level of thinker" and a killjoy; "Little Miss Pravda". And yet Wolf's answer to these bitchy attacks is mature and responsible. "Yes, she was very personal with her attacks on me, but I was very personal with my attacks on her." (Indeed she was. A scorching article she wrote in the New Republic labelled Paglia "the nipple-pierced person's Phyllis Schlafly [a rightwing activist]" who "poses as a sexual renegade but is in fact the most dutiful of patriarchal daughters", full of "howling intellectual dishonesty".)

The exchange with Paglia was, says Wolf, a "turning point" for her. "I did some serious soul-searching about what kind of life I wanted to lead; I asked myself if it was my task as a writer to level scathing personal attacks. I had a crisis because I thought, if I don't do that, then I won't have a career as a journalist, I won't go to any parties, no one will think I'm interesting. But I'm very glad I did it. It's about learning how to rebut an idea with respect for the other person. That's all." Around this time, Wolf made a "substantial personal commitment financially" to help set up the Woodhull retreat, where we meet - a non-profit institute that teaches young women "the compassionate use of power".

She can be terribly earnest - she says things like, "I feel blessed with my subject matter" and "I encountered an ethical challenge", and rather than ask if I'm Jewish, she wonders, "Do we share an ethnic heritage?" But Wolf can also be sparky and funny; when asked if the penis was the enemy, she quipped, "Hey, lots of women go home at night after a hard day's work thinking of the penis as their friend."

In fact, she encompasses several contradictions. On the one hand, she is an outspoken, visible feminist and sophisticated political operator. On the other, she often says things that cause problems for feminists and glee for anti-feminists: such as when she writes that she felt it was "dangerous" to be a feminist when her baby was young, because all that mattered was not to "rock the fragile, all-important little boat of the new family"; or discusses her white wedding dress; or says that "male sexual attention is the sun in which I bloom... the male body is ground and shelter to me, my lifelong destination"; or says she has trouble with the idea of abortion, as she wrote in Our Bodies, Our Souls. When I ask if she would have written such an article now, with Bush threatening abortion rights, she says, "Yes, I would, because I believe it is true, and I believe you have to tell the truth as you see it without bowing to situational ethics. A feminism that is not based on women speaking their truth simply won't accomplish its goals - or if it tailors the truth to meet even the most laudable goals, it will not be worth getting there in the end." (She adds that she would put a strong frame around the essay, addressing Bush's threat to abortion rights and ending with a detailed strategy and call to arms.) In other words, she believes in honesty - even if that honesty can be used by your opponents. It is a risky tactic.

And take a look at her life: it looks un-radical, encompassing all the tradition and convention of a white wedding, two children, a high-earning media husband, house in the country. Why does she write how important it is that women have certain rights, while maintaining a personal distance from those rights herself? "The reason for this difference has to do with the very definition of feminism in my mind," is her response. "To me, feminism is not a rigid set of given positions, an agenda, an ideology. It is far more radical than that: it is a premise of freedom. When the premise of freedom takes hold for women in the world, then every woman will have the right to make her own choices according to her own wisdom and conscience, and those choices will not be monolithic."

Which all sounds very well, but how long do we have to wait? "Well, before, I wanted the world to change in, say, 30 years' time," she says, pushing back the hair from her face. "Since I had my daughter, I want the world to change before she is 21. Before she is 10. Tomorrow. Yesterday."

Naomi Wolf reveals how scalpel and scissors now dominate the delivery room in the Guardian's exclusive extract from her new book, Misconceptions. Click here.