The measure has already passed through the state's legislature, dominated by the conservative Tea Party wing of the Republican Party, and Governor Bill Haslam has until today to veto it.
If passed, Tennessee would become the second state after Louisiana to allow teachers to challenge the accepted science on evolution and climate change.
Critics say the law encourages the teaching of the theory of "intelligent design," which holds that a higher being must have been responsible for the development of all life forms.
Mr Haslam, who is also a Republican, has said that he will "probably" approve the bill, which will automatically become law if he does nothing.
It is nicknamed after the 1925 "Scopes Monkey Trial," which saw John Scopes, a Tennessee high school science teacher, charged with violating state law against teaching "that man has descended from a lower order of animals". Read more...