Nearly a third of teachers believe that creationism should be given the same status as evolution in the classroom.
This includes almost one in five science teachers, according to a poll carried out by Teachers TV.
The survey of more than 1,200 teachers reveals that 31.1 per cent would like to see creationism or intelligent design taught alongside Darwin's theories of evolution and natural selection, as would 18 per cent of science teachers.
In fact, the poll found that 30 per cent of schools already tackle creationism or intelligent design during science lessons.
Terry Sanderson, of the National Secular Society, was alarmed by these findings. "Teachers seem to think it's OK to introduce creationism into science lessons, as though it's true, or real, or equivalent to science," he said. "But it isn't equivalent. It's mythology.
"It is time for the Government to issue clear and uncompromising guidance, telling teachers that not only is it unacceptable to give equivalence to creationism in science lessons, but it's banned."
When pupils raise questions about creationism during science lessons, Mr Sanderson believes teachers should recommend that they continue the discussion in RE.
"There's no way you can stop creationism being raised in science lessons," he said. "But you can jump on it."
But half the teachers surveyed disagreed with him. They supported the views expressed recently by Professor Michael Reiss, who was forced to resign as director of education at the Royal Society after he suggested that banning discussion of religious creation stories from the classroom could alienate pupils from science.
Most teachers saw the pragmatism in this approach: almost nine out of 10 felt that they should be allowed to discuss creationism during science lessons if pupils decided to raise the issue.
This approach is backed by the Church of England. A spokesman said: "If children come to you with a viewpoint, then it's a perfectly sound educational principle to work from where they are.
"The way in which people find meaning varies. Science and religion are trying to answer the same questions, but they do different jobs. Children certainly ought to be looking at creationism, and how it operated as a thesis in the past. But that should be in RE lessons."
`School Matters: Adam Rutherford on Evolution and Creationism' is on Teachers TV at 7pm on November 8.