Tennessee Gov. Bill Haslam

NASHVILLE - Tennessee Gov. Bill Haslam today allowed a controversial bill allowing teachers to discuss the "weaknesses" of evolution and other scientific theories to become law without his signature.

It is the first time Haslam, a Republican, has refused to sign a bill passed by the GOP-led General Assembly.

The legislation has been derided by critics nationwide as a modern-day "monkey bill," a reference to a 1920s Tennessee law that outlawed the teaching of evolution and spurred the arrest and trial of Dayton, Tenn., teacher John Scopes in the infamous 1925 "Monkey Trial."

"I have reviewed the final language of HB 368/SB 893 and assessed the legislation's impact," Haslam said in a statement. "I have also evaluated the concerns that have been raised by the bill. I do not believe that this legislation changes the scientific standards that are taught in our schools or the curriculum that is used by our teachers.

"However," Haslam added, "I also don't believe that it accomplishes anything that isn't already acceptable in our schools."

He noted the bill "received strong bipartisan support, passing the House and Senate by a three-to-one margin, but good legislation should bring clarity and not confusion. My concern is that this bill has not met this objective. For that reason, I will not sign the bill but will allow it to become law without my signature."

The measure was sponsored in the Senate by Sen. Bo Watson, R-Hixson. Watson's bill protects public school teachers who describe so-called "weaknesses" in evolution, climate change and other theories.

Watson has said language required teachers to discuss "weaknesses" within the "framework" of the state's science curriculum.

In a recent letter to Haslam, Vanderbilt University professor Larisa Grawe Desantis, who researches and teaches about both evolution and climate change, pointed to what she said is Tennessee's growing reputation in science education.

"But this bill points in exactly the opposite direction," she wrote.

It also will prove confusing to students, Desantis warned, noting the bill's "central premise" that scientific concepts such as evolution and climate change are "controversial" is a "disturbing and inaccurate notion."