One in eight U.S. high school biology teachers presents creationism or intelligent design in a positive light in the classroom, a new survey shows, despite a federal court's recent ban against it.

And a quarter of the nation's high school biology teachers say they devoted at least one or two classroom hours to the topics, with about half presenting it favorably and half presenting it as an invalid alternative.

Those results are part of a nationally representative, random sample of 939 teachers who filled out surveys between March 5, 2007, and May 1, 2007 on questions concerning the teaching of evolution. The figures have a 3 percent margin of error.

The research, funded by the National Science Foundation, also revealed that between 12 percent and 16 percent of the nation's biology teachers are creationists, and about one in six of them have a "young Earth" orientation, which means they believe that human beings were created by God in their present form within the past 10,000 years.

Scientists, on the other hand, agree that humans evolved from a common primate ancestor in a process that stretches back tens of millions of years. The theory of evolution on which this is based is one of the most well-supported theories in science.

By design

The highly publicized Dover ruling in 2005 banned the teaching of intelligent design in Pennsylvania public school science classes, and there have been many other legal victories at the state and local level for the teaching of evolution, but there is a disconnect between these rulings, science and what really happens in high school biology classes, said study leader Michael B. Berkman, a political scientist at Penn State University.

In the end, it is teachers, more than court cases, that determine what is presented in science class, the new research suggests.

"The status of evolution in the biology and life sciences curriculum remains highly problematic and threatened," writes Berkman and his colleagues, including Eric Plutzer and Julianna Sandell Pacheco, both of Penn State, in a peer-reviewed essay on the survey in the latest issue of the journal PLoS Biology.

Berkman and Plutzer have a longstanding project that focuses on the responsiveness of school districts to public opinion.

"This issue [the teaching of evolution] is particularly interesting in that context because the public opinion on it is in many ways so far away from where the experts are," Berkman told LiveScience. For instance, about 38 percent of Americans would prefer that creationism be taught instead of evolution, according to a 2005 poll by the Pew Forum on Religion and Public Life.

Hottest button

Other details of the survey results:

- The majority of biology teachers spend between 3 and 15 hours on evolution, which the National Academy of Sciences considers to be the most important concept of biology.

- The majority of teachers spend no more than five hours on human evolution.

- Only 23 percent of teachers strongly agreed that evolution is the unifying theme for their biology or life sciences courses, though the majority of teachers see evolution as essential to high school biology.

- The more biology or life sciences classes taken in college by a teacher, the more evolution they taught.

"This is the hottest of the hot buttons," Berkman said of the teaching of evolution. Even the strongest legal ruling "still gives boards of education, school districts and especially teachers considerable leeway."

Victory in the courts and state standards will not ensure that evolution is included in high school science classes, Berkman and his colleagues conclude. A bigger impact would come by focusing on certification standards for high school biology teachers, such as requiring all teachers to complete a course in evolutionary biology.

Berkman said he didn't know if this was likely to happen, but he hopes the new research "captures the attention of people who make decisions on that, science educators as well as scientists."