The Humanist Society of Scotland has launched a campaign calling on the Government to give it parity of esteem in education with those who hold religious views.
The campaign, which cites the United Nations Convention on the Rights of the Child as support, has won the backing of the playwright and novelist Christopher Brookmyre, who has become the society's first president.
He said: "Children necessarily must invest the sincerest trust in what their teachers tell them. Thus the same institution that tells them one plus one equals two should not then be telling them that three persons add up to one God."
The society has also made available free teaching and support materials.