Only one month into 2013, at least five states are considering bills that would allow or promote creationist theories in science class: Missouri, Montana, Colorado, Oklahoma, and Indiana. Of course, not all of these bills will pass – but some of them may.
The most pro-creationist of the proposed laws is a bill introduced in the Missouri House of Representatives, which requires biology textbooks to give "equal treatment to biological evolution and biological intelligent design." The bill also mandates that "biological evolution and biological intelligent design shall be taught" in all classes on the origin of life.
Missouri's is the only bill that requires that intelligent design to be taught in biology class. The other bills allow teachers to introduce it if they wish.
The Supreme Court declared bills requiring intelligent design unconstitutional in the 2005 case Kitzmiller v. Dover.
Missouri already has a law requiring teachers have students "critically analyze" evolutionary theory. Texas, Minnesota, New Mexico, Pennsylvania, South Carolina, and Alabama all have similar requirements, while Louisiana, Mississippi, and Tennessee allow alternatives to evolution in the classroom, but don't require them.