Teachers should abandon their cloak of neutrality and tell pupils their views about controversial science topics such as genetically modified crops and the MMR vaccine, a conference was told this week.
Justin Dillon, a science education lecturer, said pretending to have no opinion on issues in the news was unethical.
Science teaching was dominated by a philosophy that saw the subject as neutral, objective and dispassionate, he said.
But Mr Dillon, from King's College, London said debates on issues such as the measles, mumps and rubella vaccine and GM crops raised questions of morality as well as science.
"Taking a neutral stance is not a good strategy for teaching children how society works. It is unethical to pretend to pupils that teachers have no opinion," he said.
Mr Dillon's comments at the British Association Festival of Science at Exeter university follow research involving more than 200 teachers, focus groups, classroom observations and inspection findings. He presented research carried out with Chris Oulton, Gloucester university, Marcus Grace, Southampton university and Vanessa Day, University college, Worcester. The findings are published in the latest issue of Development Education Journal.
Mr Dillon said: "The traditional approach to leading a discussion on a controversial science subject is for the teacher to take a neutral role. We believe that strategy is wrong.
"Teachers should be open with their own biases rather than pretend to be neutral and students should be asked to take any bias into account when making up their minds," he said.
Earlier, Mary Ratcliffe, director of Southampton university's Science Learning Centre, warned that ethical and social issues arising from scientific advances were often marginalised in schools despite being part of the curriculum.
Science teachers blamed a lack of time, and the fact that both curriculum and exams focus on traditional content. They also found it harder to teach a topic when there was not a single, correct answer.
Dr Deborah Cotton of Plymouth university, told the festival that she had conducted a study that bore out Mr Dillon's points. A-level geography teachers at three schools had been observed raising controversial environmental issues for discussion with pupils.
The teachers had tried to teach topics from neutral perspectives, but Dr Cotton found it easy to discern their views.
"The teachers all supported taking a balanced view in the classroom, but when it came down to it, that was a position that was very difficult to maintain. Students would also have been able to (work out their opinions)."