The sexual health and relationships programme was created to find out whether specially designed, theoretically-informed sex education had any effect on young people's sexual risk-taking and the quality of sexual relationships.
But although it provided information, it did not change behaviour. The researchers suggested this may be because sex education in Britain does not give young people any explicit direction on what to do - whether to wait for the "right person" or, more pragmatically, to always use contraception.
The SHARE programme, set up by the Medical Research Council's social and public health sciences unit in Glasgow, was used with two cohorts of S3 pupils - in 1996 and 1997 - in 25 east of Scotland schools. The subsequent impact on young people's lives was evaluated between 1996 and 2006, resulting in one of the world's most thorough evaluations of sex education.
It was more rigorous than usual, with personal and social education teachers undergoing five days' training as opposed to training of less than one day. Pupils took part in 20 sessions over two years.
Moreover, the sessions in-cluded active learning, interactive videos, role playing and demonstrations with condoms. Stan-dard sessions are more infor-mation-based and have little emphasis on developing skills.
The young people were shown to be more knowledgeable about sexual health having been through the programme. Yet it was found that by the time they reached 16, they were no different to peers in when they first had sex, number of sexual partners, and use of contraceptives. By 20, NHS figures showed no change in the number of abortions.
Daniel Wight, who led the study, suggested a number of reasons for such minimal impact. Despite the increase in time devoted to such education, this had a weak effect in relation to the more pervasive influences of the mass media, family, local culture and economic factors.
British sex education may also be weak in influence because it is not prescriptive. Dr Wight said there is a greater impact where specific courses of action are recommended, whatever they might be.
He feels that personal and social education has low status in schools and is not viewed as a serious subject by pupils. Moreover, sex education seems most effective when a young person is thinking about starting a sexual relationship; for many pupils, the programme came along too late, for others too early.
Anna Glasier, NHS Lothian clinical lead of sexual health, told the Holyrood Events sexual health conference in Edinburgh last week that providing contraceptives and sexual health services in certain schools could redress high pregnancy rates.
In response, public health minister Shona Robison said some schools offered "limited" contraception through health professionals, but that emergency contraception should be provided elsewhere.