The world's top scientists have joined forces to call for "evidence-based" teaching of evolution in schools.
A statement signed by 67 national science academies says evidence on the origins of life is being "concealed, denied, or confused" in some classes.
It lists key facts on evolution that "scientific evidence has never contradicted".
These include the formation of Earth 4.5 billion years ago, and the onset of life at least 2.5 billion years ago.
"We know of schools in various parts of the world where the children are told that the Earth is about 8,000 years old," said Yves Quere, co-chair of the Inter Academy Panel on International Issues, the global network of science academies.
"So in this statement we say you cannot teach this to children, it is wrong."
Dr Quere said the statement reflected growing concern within the scientific community that children were not being taught basic facts on evolution and the nature of scientific inquiry.
"In some countries, the simple theory of evolution is denied in the teaching of children in schools," he said.
The acadmies' statement says: "We urge decision-makers, teachers, and parents to educate all children about the methods and discoveries of science and to foster an understanding of the science of nature.
"Knowledge of the natural world in which they live empowers people to meet human needs and protect the planet."
Its release follows fierce debate about whether so-called intelligent design (ID) should be taught in biology courses in schools, mainly in the US.