The children of De Burght School in Amsterdam walk past the red-light district to their classrooms every day, past the “Peep Shows, Live Girls,” the risqué underwear shops and the newsagents selling teen magazines with free condoms. At school the five-year-olds play mummies and daddies in the playground knowing what their parents did in bed last night.

Next year, 12-year-old Sasha explains to me, they will learn how to put a condom on a broomstick (she says this without a trace of embarrassment, just a polite smile). Across the city, nine-year-old Marcus, who lives in a beautiful 18th-century house on a canal, has been watching a cartoon showing him how to masturbate. His sister, 11, has been writing an essay on reproduction and knows that it is legal for two consenting 12-year-olds to make love. Her favourite magazine, Girls, gives advice on techniques in bed, and her parents sometimes allow her to stay up to see a baby being born on the birthing channel.

Then there is Yuri, 16, who explains to me in perfect English that “anal sex hurts at the beginning but if you persevere it can be very pleasurable”. When I ask whether he is gay, he says “no” but he has watched a documentary on the subject with his parents.

Sex is everywhere in the Netherlands, yet the country has the lowest teenage pregnancy rate in the West and the lowest rates of sexually transmitted diseases among young people. Now Britain, with almost the highest rate of teenage pregnancy in Europe - five times higher than the Netherlands - wants to emulate its success.

Ministers are planning to introduce compulsory sex and relationships lessons for children from the age of 5 by 2010. There will be a “naming of parts” session in which children learn the correct words for vagina and testicles, and many will receive a sex education comic called Let's Grow with Nisha and Joe.

The Government has chosen the Dutch model rather than the Nordic way of tackling the subject of sex because the Netherlands, unlike Scandinavian nations, also manages to have one of the lowest abortion rates in Europe. In Britain, the number of abortions performed on under-16s rose by 10 per cent last year to 4,376.

So how do the Dutch do it? Siebe Heutzepeter, the headmaster of De Burght School, laughs at the idea that sex lessons are all children need to stop them becoming sexually active too young.

“We don't have formal sex education in primary schools,” he says. “The children talk about sex when they feel like it and when they want an explanation. We treat sex as a healthy physical activity between two adults who are in love. Every year we have teachers who are pregnant or getting married, whether they are gay or straight, so it is a good way to talk about adult relationships.”

Heutzepeter says that the Dutch are more relaxed than Britons in every aspect of their lives. “The English are embarrassed to talk about sex. They are too squeamish. Here adults and children are better educated. It would be unthinkable for a Dutch parent to withdraw their child from sex discussions. I have had only one Muslim mother who left halfway through a parents' talk on sex.”

He believes it is important to talk to children in a relaxed way about sex before they become self-conscious and embarrassed. “It is all about self-respect,” he said. “There is no point in telling children just to say ‘no' - this is a liberal country; you need to tell them why they are saying ‘no' and when to say ‘yes'.”

A series of books by Sanderijn van der Doef provides Dutch children with all they could need to know about sex. The book for five-year-olds has pictures on the cover of toddlers kissing each other on the lips. Inside, children are told why their mothers have breasts and shave their armpits, how smiley-faced sperm travel, how human beings prefer to lie on top of each other but dogs mate from behind, and what their father's penis looks like. The book for 11-year-olds shows a girl examining her genitals in a mirror, and explains about periods and the Pill.

Van der Doef is a star in her country and her manuals have become classics. Dutch parents read them to their children at bedtime, for information and enjoyment. “Here sex is a normal daily part of life, like shopping or football. In England it is a joke,” says the author. “My books teach children what adults do when they love each other and how babies are created. Children as young as 4 should know if they were born by Caesarean section or after artificial insemination. It is vital to be honest.”

John van der Woning, the head of one of Amsterdam's leading schools, Willemspark, says: “We teach children about all sorts of sex. We have lots of homosexual teachers and they celebrated a marriage of two female teachers recently. But we also try to teach the older children about the darker side of sex, about prostitution and child abuse. It's important to be open about the world.”

At secondary school the sex education is formalised and children are shown how to use various types of contraceptive, how to have “safe and pleasurable sex”, the importance of responsibility and how to recognise the symptoms of sexually transmitted diseases.

This openness seems to work. In Britain the average teenager loses his or her virginity at 16 - more than a year before the Dutch average of 17.7 years. About 93 per cent of young people in the Netherlands use contraception, compared with 53 per cent in Britain. A study of teenagers in both countries found that while boys and girls in the Netherlands gave “love and commitment” as the main reason for losing their virginity, boys in Britain cited peer pressure and physical attraction.

But Laura Watts, a British mother who has lived in the Netherlands for the past ten years, thinks that the lower rate of teenage pregnancy there may have more to do with family structure than with sex education. Dutch children are five times less likely to be living in a family headed by a lone parent, divorce rates are far lower and fewer mothers are in full-time employment.

“I think my eight-year-old son has probably learnt more about sex from David Attenborough than from school,” she says. “It is the family that makes the difference. Parents leave the office by 5pm in Holland and eat dinner with their children at 6pm. They then watch TV or play sport together, so they tend to be closer to their children and can guide them to do the right thing.”

Trudie, a fashion stylist, has always talked about sex with her daughter. When, at 16, her daughter asked her what sperm looked like, Trudie asked her husband to provide a sample. “My daughter walks past sex shops every day, the family watches sex scenes together on television and we try to be as open as possible. It's not considered smutty, as it is in England.”

Henny de Barbarison, a teacher at De Burght School, agrees: “My 18-year-old son still walks around the house naked - that's healthy. Everyone here is more relaxed.” Her female students are taught about “lover boys” who flirt with girls just to have sex with them, then pressurise them to sleep with other members of their group. Male students are taught about homosexual sex. There are no “no-go areas”.

Another reason why the teenage pregnancy rate is so low may be that in the Netherlands there is still a stigma attached to having a child before the age of 20. In Britain, a baby who can offer unconditional love, a free home away from parents and a cheque every month is not considered a disaster for a teenage girl. The Dutch Government still penalises single mothers under 18, who are expected to live with their parents if they become pregnant. Until six years ago the Government gave them no financial support.

Dutch children are taught that getting pregnant in their teens is a barrier to success. “I'm not prepared to risk messing up my life. I am strong enough to wait,” says Ruby, 12. “I want to be 19 and in love before I have sex,” says her friend Grace. Julia, 11, says: “My mother's best friend is gay, my hairdresser is gay, half my family seem to be gay. It's not an issue.”

Children in their final year of primary school have not been shielded from anything, but their teachers have continually reinforced the message that sex is about love and commitment. The pupils all agree that they will not sleep with anyone until they have finished secondary school and are in a serious relationship.

Vanessa Storm de Grave, a mother of four who works part-time for a publishing company, thinks that her compatriots may be more responsible about sex than the British because the Netherlands is a more religious country. “The family is very important here,” she says. “Almost no mothers work full time; they see their main role as educating their children.

“I hope I will teach my eldest son how to become a responsible man by example, but I tell him anything he wants to know. I have talked about homosexuality and why it means that you can't have babies, but he is more interested in sport.”

Doortje Braeker, a Dutch mother who works in Britain for the International Planned Parenthood Federation, says: “We are not scared of young people being sexually active and we want to make sure that their first experiences are safe and pleasurable. We are a Calvinist country so it is important that we don't have too many abortions, but the postwar generation also wants to have fun.”

Braeker was shocked when she first came to Britain. “Young girls here seem to have babies to prove that they are adults. In the Netherlands it would just prove how uneducated and naive you are,” she says. “There you can have a boy as a friend, here it's almost always about sex.”

Mena Laura Meyer, who produced the seven-part documentary series Sexy for Dutch TV last year, says that sex education is the least relevant aspect of the country's success. “All the children I talked to were quite dismissive about their sex education at school,” she says. “They appreciated knowing how to put on a condom but were more interested in the emotional than the physical side of sex.”

Her series, which addressed every issue from anal sex to S&M, was watched by more than a quarter of Dutch households. “All you watch in Britain are your soaps, which are all about single mums, and your wildlife documentaries, which just cover penguins mating,” she says. “Sex and relationships aren't government issues. Until the British can sit down together and watch programmes about masturbation and birth, you will never have a healthy attitude to sex.”

In Britain the Government has decided that schools must bear responsibility for sex education. Jim Knight, the Schools Minister, insists that from 2010 schools must make time for the new personal, social and health education (PSHE) syllabus. Children aged 5 to 7 will learn about feelings; those aged 8 to 11 will be taught about the biological aspects of sex. At secondary school they will learn about contraception and sexually transmitted diseases.

But maybe it's up to parents. Perhaps we should all be buying our toddlers Mummy Laid An Egg by Babette Cole, leaving condoms around the house, as one Dutch mother suggests, “to prompt discussions”, and sitting down to supper each evening to discuss our relationships.

One colleague attempted this, and her 12-year-old son asked her “how many positions are there?” in front of the babysitter. My eight-year-old asked me if it was more painful to wax my legs than to give birth.

But after my few days in the Netherlands, my children now understand where babies come from. It has marred the beginning of Dumbo when the storks come down from the clouds, but I hope it will turn them into more responsible adults.

Maybe, instead of expecting schools to teach children morality and the missionary position, the British should adopt a few other Dutch lessons. Employers could encourage staff to go home at 5pm for a family supper, parents could discuss contraception with their children, and the BBC could ask David Attenborough to turn his attention to human reproduction.

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