The experiment, among 400 teenagers at Devon schools over three years, has proved that a "high-quality" sex-education programme involving doctors and peers confounds the idea that sex education increases sexual activity, the authors say.
Dr John Tripp and Dr Alex Mellanby, of Exeter University's department of child health, agreed yesterday that their programme, costing about pounds 45 per child during a school career or pounds 1,000 per class, was expensive.
However, Dr Mellanby said that local authorities and health authorities were realising that education budgets were too tight and that cross funding would be necessary. Effective health education was cost beneficial in terms of reduced abortions, improved sexual health and reduced demand on social services, he said. His own local authority and one Essex authority are to use the programme next year, covering 2,000 teenagers.
The survey is published in the British Medical Journal with new information from another report from the national survey of sexual attitudes and lifestyles in 1991-92, funded by the Wellcome Trust, which came to similar conclusions.
The authors of the latter say "confidently" they can find "no evidence to support the concern that provision of school sex education might hasten the onset of sexual experience".
Jane Wadsworth, one of the authors of the survey of 18,876 adults, said yesterday: "Over 10 years the use of condoms among people having sex for the first time has increased from 30 per cent in 1981 to 60 per cent in 1991."
Dr Richard Smith, editor of the BMJ, said: "One in six young women gets pregnant under the age of 18 and most of them wish they weren't. We get a lot of heated opinion about sex education in schools but not too much data . . . Good sex education can change behaviour. Here we have the evidence that this can be done.
"One of the problems is that a lot of schools tend to be nervous about sex education fearing a backlash from the local community. High-quality sex education is likely to lead to sex later and more likely to lead to protected sex," he said.
Key elements of the programme are: being taught by independent health professionals; learning with 17- to 18-year-olds who have had 25 hours of training; setting ground rules for sessions - no personal comments or put-downs; and teaching the art of saying "no".
In the Devon survey, three school years of teenagers from 13 to 16 were included in the programme. The results were tested by comparing knowledge, attitudes and behaviour with teenagers at other local and distant schools.
"Students (aged 15.5 to 16.5) in 1994 in the whole control group were 1.45 times more likely to have had sexual intercourse than students within the programme population," the report says.
Dr Mellanby said that after the programme the teenagers knew more about sexually transmitted disease and contraception, and were less likely to believe myths, such as "you can't get pregnant if you do it in the bath".Reuse content