The Kansas state school board has begun four days of hearings into how children in state schools are taught about the origins of life.
Darwinian theory would be challenged with "alternative explanations"
Religious conservatives are pressing for a change to state guidelines that would play down Charles Darwin's theory of evolution.
They argue that the teaching of evolution shows a bias against religion.
Science organisations have boycotted the hearings in protest.
A three-member Board of Education sub-committee called the hearings to consider revisions to the state science teachings standards.
In June, they will decide whether to revise the science curriculum to include criticisms of the principles of evolution as an explanation of the way life changes over time.
Teachers would be encouraged to discuss "alternative explanations".
The hearings are complete with opposing attorneys and a long witness list, although the witnesses are all allied against the teaching of evolution.
Many of the witnesses support "intelligent design", the belief that scientific evidence cannot account for the complexity of the Universe and that it must be the result of some higher power.
Schools were teaching that life evolved naturally and randomly, in conflict with Biblical teachings on the creation of life, said William Harris of the Kansas-based Intelligent Design Network.
"Part of our overall goal is to remove the bias against religion that is currently in schools," said Mr Harris, who works as a medical researcher.
National and state science organisations are boycotting the hearings saying that they are rigged against evolution.
Detractors have compared the hearings to the 1925 Scopes Monkey Trial in which a teacher in the state of Tennessee was convicted of breaking a law against teaching evolution.
Instead of testifying at the hearings, science groups are holding daily news conferences.
On the opening day of the hearings, they rolled out a wheelbarrow and two crates full of scientific journals full of arguments and evidence supporting evolution.
"This is a showcase trial," said Jack Krebs, vice-president for Kansas Citizens for Science. "They have hijacked science and education."
The 'evolution wars'
Kansas has been one of the key battlegrounds in what some are calling the "evolution wars".
In 1999, Kansas made headlines as the conservative majority on the state board voted to play down evolution in state science teaching.
School boards in a dozen states in the US are grappling with the issue and the renewed challenge to evolution from supporters of "intelligent design".
But despite these efforts to limit the teaching of evolution, state schools in the US are prohibited from teaching Biblical views on the origins of life, also known as "creationism".
The US Supreme Court ruled in 1987 that creationism could not be taught in tandem with evolution.