Parents should talk to children as young as 11 about sex informally and often if they want them to delay sexual experiences and take fewer risks, according to the Government.

A report that will form the basis of a national campaign has identified the ages from 11 to 14 as the essential time for parents to talk about sex and relationships with their children. Once a teenager turns 15 there is little chance that what parents say will have any impact.

Research for the report, Everyday Conversations Every Day, conducted by Populus, found that 75 per cent of 11 to 14-year-olds want their parents to talk to them about sex, and 44 per cent do not trust what they hear from friends. Twenty-five per cent said they were confused about the basics of sex despite all they heard in the playground and on television.

The report advises against a serious one-off “facts of life” conversation and recommends bringing up the subject of sex informally and frequently when the opportunity arises during television programmes or while reading magazines.

Ministers are searching for new ways to tackle Britain's problem with teenage pregnancy and deteriorating sexual health. England and Wales have the highest rates of teenage pregnancy in Europe, and infection rates of sexually transmitted diseases are climbing steadily.

Many parents use sex education in school as an excuse not to discuss the topic at home but the only legal requirement made of schools is that they teach children the basic facts about human reproduction. The report will form the basis of a campaign fronted by Anita Naik, the teenage agony aunt for magazines such as Bliss. She said: “Teenagers unanimously agree that parents who speak to them about sex are in no way encouraging them to go out and do it. Having everyday conversations as often as possible about sex and relationships is proven to reduce risky behaviour and can help young people make measured decisions about sex and stay safe.”

ParentlinePlus, the charity helpline, is also involved in the campaign and will carry information on its website on how to raise the subject of sex.

Case Study Marian O'Regan

The mother of two, from Essex, has always found it easy to talk to her daughter about sex. Hannah, 11, has given her a way into the conversation when she has watched, with horror, teenage girls in soap operas getting pregnant.

“It has allowed me to talk to her about what it may be like when she is a bit older, and falls head-over-heels in love, or how a boy she likes might want to encourage her to take risks or do things she isn't comfortable with,” Mrs O'Regan, 40, a criminal justice adviser in the Metropolitan Police, said.

She is, however, anxious about how she is going to talk to her son, Sean, who turns 9 this year. “When he hears about teenage girls getting pregnant he doesn't think it concerns boys, and somehow boys only become fathers when they are older and get married, so he has a lot to learn. But I just don't think I am in a position to tell him that when he is older he will feel certain things, and have to learn to control his urges. I might leave it to his father.”

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