'The baby came out under the water - they don't breathe until they hit the surface. I pulled him out of me. It was the coolest thing.'

This is ex-talk show host and actress Ricki Lake, 39, talking about what it was like to give birth - at home in her bath. And now she wants the world to know about the power of her self-styled 'awesome vagina'. She has executive-produced a graphic campaigning documentary, The Business of Being Born, about to go on general release in cinemas across the US. And why not?

Suddenly homebirth is hip. All the celebs are doing it - so it must be. US Vogue devoted five pages to the subject in its November issue and Ricki Lake's film is the talk of Hollywood. Some extraordinary celebrity home-birthers have been revealed: Pamela Anderson, Kelly Preston (Mrs John Travolta), Cindy Crawford, Lisa Bonet and Demi Moore (who had all four of her children at home). Increasingly, midwife-attended, planned homebirth is something that a certain kind of woman is clamouring for. In the current cultural climate it was only a matter of time before it got celebrity endorsement, and its very own movie.

In the US one per cent of babies are born at home: in the UK it's two per cent. Over here, we have celeb home-birthers too: Davina McCall is the poster girl for the movement (three deliveries at home, including her first child). And in September last year Charlotte Church gave birth to her first baby, Ruby Megan, 6lbs, at home in South Wales after having a birthing pool installed. Thandie Newton, models Kirsty Hume and Stella Tennant, Jade Jagger, Jemma Redgrave, Nelly Furtado, Smack the Pony's Doon Mackichan have all had homebirths.

The Ricki Lake film shows what can only be described as extremely graphic footage of the birth of second son Owen, now six. Online magazine Salon described it as 'the opposite of a celebrity vanity project'. Those of us who have already watched the highlights on YouTube are inclined to agree - although possibly in less delicate, less mature terms, and with added gagging.

Newly svelte after shedding 25 pounds (again), this documentary is part of Lake's reinvention as a campaigner and advocate for women's rights. She recorded her last talk show in 2004 and has no plans to return. Speaking from her home in Los Angeles, Lake says she feels a bit uncomfortable about the home video, which was not recorded for broadcast: 'It's a beautiful moment but I don't think I look my best. I am naked at 195lb giving birth in my own bathtub. It can't get any more intimate than that!'

She felt it was important, however, to show why she made the decision to have a homebirth: 'I felt like stuff went on during the [hospital] birth of my first son, Milo, now 10, that was out of my hands. With hindsight I felt like the hospital protocol was not what is necessarily best for mother and baby. The second time I researched hard. I found a midwife who was comfortable with me giving birth in water at home. Everyone told me I was crazy - in the US less than one per cent give birth outside hospital. But it's a misguided fear. I believed in my body: I had already given birth vaginally so I knew I could do it.' Studies suggest that homebirth is at least as safe as hospital birth - but the myth still persists that hospital birth is 'better'. Ricki Lake's film takes the view that the hospital experience in the US is too time-pressured and overly managed. It shows home delivery warts and all - and, as I say, is not a viewing experience for the squeamish. Lake doesn't believe homebirth is for everyone - but thinks women should be free to choose. In America there is little choice. One in every three hospital births ends in C-section (when the World Health Organisation recommends a Caesarean rate of between 10 per cent and 15 per cent). And it is illegal to practise as a home-birth midwife in 10 of the States. 'I'm not dissing hospitals,' Lake says. 'We need necessary C-sections. But we also need to choose an empowering birth experience. Giving birth to my baby at home has left me with such a feeling of power - you feel like a superhero. Everything in our culture perpetuates the myth that birth is scary. We focus on what can go wrong, all the horrifying details. We've tried to make a documentary that is positive, with great birth stories, so that women can feel confident.'

Nonetheless, she accepts that a homebirth involves pain: an epidural can't be administered at home (midwives carry gas and air): 'I am not a martyr or a masochist. But I feel like I needed to feel everything that I felt. In the end I describe it as manageable pain: I only pushed for 13 minutes. With my first, I pushed for two-and-a-half hours.'

Davina McCall - who shouts 'I am the homebirth evangelist' down the phone at me - decided on homebirth when she heard a friend talking about it. 'She was the first person I had met who said the words, "I love giving birth". I thought: is she mad? Why? How? She talked about empowerment, how peaceful and relaxing it was, how she dealt with her pain in a unique way. I thought: I want what she's got.' Initially her husband, Matthew, was not keen: 'He wanted to see the statistics in black and white. Are you more at risk at home? No. Are you more at risk of your child dying? No. In fact you are less likely to have intervention that can lead to complications if you are at home.' She gave birth to all three children - Holly, six, Tilly, four, and Chester, one - in water with no drugs, not even gas and air. Each time she took two paracetamol and used a TENS machine until she got into the birthing pool. And she repeated a mantra to herself: God only gives you as much pain as you can handle. 'As an ex-drug addict, the endorphins are the best high I've ever had.'

Like Ricki Lake, though, McCall does not think homebirth works for everyone. 'I've got friends who think epidurals are the best thing since sliced bread. And friends who have had elective Caesareans. You don't get ridiculed for those choices. And I don't want to be ridiculed for mine.' She laughed at anyone who told her she was 'brave' to try homebirth: 'I just said to them - no, you're brave going into hospital. I don't want MRSA, thank you very much.'

A lot of people actually find homebirth the least scary option, says Safia Minney, 43, founder of the ethical fashion label People Tree. She had both her children, Natalie, 11, and Jerome, 14, at home, when she was living in Japan. 'I looked at supposedly baby-friendly hospitals and I could see these stirrups everywhere. The sight of those things just made me go cold.' Her son was born at home after about seven hours: 'The midwife brought oxygen [gas and air] but not much else. I remember her saying on the phone to the hospital after about five hours, "I think the baby is stuck..." It just made me work a bit harder.' Having babies at home is less stressful than going into hospital, she says. 'I went back to working from home after a few days. It was all pretty seamless and I loved that. I was very pleased to be in control of everything.'

Homebirth is now high on the political agenda in Britain: the government claims it wants to increase the number of homebirths. That may be a long way off - realistically, midwife staffing levels are far too low to facilitate this. In recent years there was a rise in the two per cent of mothers who give birth at home - up to 17,000 in 2005 from 15,000 in 2004.

Increasingly, middle-class women are hiring their own midwives to attend their homebirths (at about £2,000 a pop), although new legislation is making this more difficult (private medical insurance is difficult for midwives to obtain and it's illegal to practise without it).

The problem, says McCall, is that we are obsessed with birth being risky, when it's not. 'It isn't a weird thing for a birth to go well - that's the notion we have to get out of our heads. When I was pregnant someone I knew said to me, "I know somebody who gave birth at home and their baby died". I thought: why did you tell me that? Babies die in hospital all the time.

'Instead, empower someone: tell them it's going to be amazing. Fear is a real enemy to childbirth.'

Ricki Lake agrees. She wishes that every woman could share in the power of her 'awesome vagina': 'I had an amazing experience. I loved every minute of it. And I felt like I was the only woman ever to give birth.' As someone - or indeed, quite a lot of people - once said: go, Ricki.

· See birthchoiceuk.com, a public-information website, and the National Childbirth Trust at nct.org.uk