New research shows many public high school biology teachers are not comfortable teaching evolution.

The Penn State study surveyed 900 teachers and found 60 percent were "uncomfortable and ambiguous" with the subject.

Thirty percent were solid on their instruction of the controversial topic, and 13 percent were advocates of creationism.

"The survey left space for (the teachers) to share their experiences. That's where we picked up a lot of a sense about how they play to the test and tell students they can figure it out for themselves," Michael Berkman, co-author of the study with Penn State University colleague Eric Plutzer, told Livescience.

"Our general sense is they lack the knowledge and confidence to go in there and teach evolution, which makes them risk-averse," he explained.

Berkman said those that are uncomfortable undermine science by offering an "inadequate portrayal of evolutionary biology."

Researchers stated that all major federal court court cases in the U.S. in the past 40 years regarding efforts to try to get creationism into science classrooms have failed.

"We say (evolution is) a central idea in biology, but someone can get a biology degree and not take a class in it," Randy Moore, a science and evolution education specialist in the biology department at the University of Minnesota who was not involved in the study, told LiveScience. "We let that go in the name of religious freedom."

--Originally published Jan. 28, 2011.