The findings suggest that science teachers prefer to stick to the facts - despite the revised secondary curriculum emphasising requirements to discuss controversial and ethical issues and the

historical development of scientific ideas.

The survey, carried out for the Wellcome Trust by the London Institute for Education, looked at how biomedical research issues are addressed in schools at post-14 and post-16.

Questionnaire responses from 305 schools and interviews at 20 revealed few had policies on teaching controversial issues, such as bioethcs. Teachers said they had taught a range of issues - from HIVAids (70 per cent) to genetic engineering (50 per cent) to brain tissue transplantations (fewer than 5 per cent).

But the institute’s Ralph Levinson, speaking at last week’s Association for Science Education conference, noted: “Non-scientists felt more confident about teaching science and ethical issues than science teachers did.

“Science teachers found it very difficult and felt nervous about handling controversy. They tend to see themselves as dealing with facts as distinct from values.

“It may be the case we ought to be putting some effort into teaching socio-scientific issues through humanities.”