The new group's website has lesson ideas for science teachers
Parents are being encouraged to challenge their children's science teachers over what they are explaining as the origins of life.
An organisation called Truth in Science has also sent resource packs to all UK secondary school science departments.
It promotes the idea of intelligent design - that there was an intelligence behind the creation of the universe.
Humanists and a Christian think tank want the government to tell teachers to keep "a wholly scientific perspective".
The Department for Education and Skills (DfES) in England has said it does not endorse the resources sent out by Truth in Science.
It said the fossil record was evidence for evolution.
Truth in Science challenges this, and says much of what is taught in school science lessons about the origin of the living world is "dogmatic and imbalanced".
In its cause, it refers to what the national curriculum in England says about pupils being taught "how scientific controversies can arise from different ways of interpreting empirical evidence (for example, Darwin's theory of evolution)".
It says few schools have done this.
But the new GCSE science syllabus that schools have begun teaching this term brings "a fresh opportunity to reconsider what is taught about origins".
It quotes the Edexcel examining board as explaining that students "need to adopt a critical, questioning frame of mind, going 'behind the scenes' to understand the workings of science and how it impacts on society and their lives".
The Truth in Science website says: "We consider that it is time for students to be permitted to adopt a critical approach to Darwinism in science lessons."
It tells parents that what their child is taught in school "may profoundly affect his or her attitudes and future life".
"Does your school take a fair and balanced approach to the teaching of origins in science?"
It suggests ways they can check up.
"If you wish to improve science education at your child's school, please point teachers towards this website."
The British Humanist Association and the progressive think tank Ekklesia have written to Education Secretary Alan Johnson, calling on the government to ensure teachers know that teaching material provided by Truth in Science "is not appropriate for school science".
Ekklesia co-director Simon Barrow said: "Reputable scientists and reputable theologians are clear that the anti-evolutionary ideas propagated by groups like this are in no way comparable to scientific theories of origins.
"The government and its inspectorate should have no truck with superstition in the modern science classroom."
A spokesperson for the DfES said: "Neither creationism nor intelligent design are taught as a subject in schools, and are not specified in the science curriculum.
"The national curriculum for science clearly sets down that pupils should be taught that the fossil record is evidence for evolution, and how variation and selection may lead to evolution or extinction."