A new Tennessee law protects teachers who explore the “scientific strengths and scientific weaknesses” of evolution and climate change, a move science education advocates say could make it easier for creationism and global warming denial to enter U.S. classrooms.

The measure, which became law Tuesday, made Tennessee the second state, after Louisiana, to enable teachers to more easily teach alternative theories to the widely accepted scientific concepts of evolution and human-caused climate change. At least five other states considered similar legislation this year.

The heart of the law is protection for teachers who “help students understand, analyze, critique, and review in an objective manner the scientific strengths and scientific weaknesses of existing scientific theories covered in the course being taught.”

Science education advocates say this leaves latitude for teachers to bring in material on creationism or climate change denial, which they consider unsound science.

The law was billed as a triumph of academic freedom by proponents of creationism or intelligent design, who reject the concept that human beings and other life forms evolved through random mutation and natural selection.