In the United States there is a growing debate over what school children should be taught about the origins and development of life.
Most of the scientific community supports the theory of evolution, which says life evolved over time into more complex organisms.
But a number of school boards have added an alternative theory to their curriculum called Intelligent Design, which argues living organisms are so complex, an intelligent force must have been involved in creating them.
A court case in the eastern U.S. state of Pennsylvania could influence the way science is taught in this country. At issue is whether school children should be taught Intelligent Design as an alternative theory to Evolution.
Richard Thompson, a lawyer representing the school board that has endorsed Intelligent Design, believes the case is about the freedom to present an alternative to evolution, which was first proposed by Charles Darwin.
"It is the ability of school boards to allow public students to know other theories besides Darwin's theory."
But the state's legal director, Vic Witold Walczak, says introducing Intelligent Design into the curriculum is an attempt to sneak religion into public schools.
"We expect to show the motivation here locally was to undermine evolution and to teach a religious concept," said Mr. Walczak.
Opponents of Intelligent Design, like Alan Leshner, the head of the American Association for the Advancement of Science, say it is nothing more than the biblical account of creation in a new wrapper.
"There is nothing scientific about intelligent design as a concept. And therefore we see no reason to teach it in the science classroom. It's not an alternative to evolution as an explanation or a scientific theory."
In 1987, the U.S. Supreme Court ruled that public schools could not teach creationism because it violated the constitutional ban on establishment of an official religion.
Intelligent Design supporters say it is not creationism. They argue that, given the intricate structures in nature, the only explanation is an intelligent influence.
Mark Ryland is with the Discovery Institute, a driving force behind the idea that Evolution is just one of several theories.
"Intelligent Design theory says, although we can argue about specific ways in which an intelligent cause can interact with nature, the best inference for the data we see is some kind of intelligent causation."
Most of the scientific community, including Alan Leshner, believes evolution is a proven explanation of how organisms have changed or evolved to adapt to changing environments.
"Evolution is far more than a belief or an educated guess about how people came to be as they are,” said Dr. Leshner. “It is, in fact, the product of converging evidence from many, many different fields of science. Many, many thousands of studies that, in fact, have provided a theory, an organizing principal in fact, that describes how humans came to be."
While most scientists see no need for alternative theories, a poll earlier this year found nearly two thirds of Americans believe creationism or Intelligent Design should be taught in public schools. Among them is U.S. President George W. Bush, but he believes the decision should be left to the states. Twenty-eight are considering it.
Mark Ryland, of the Discovery Institute, says that may not be necessary. He believes it is more important to teach high school students to view evolution with a critical eye.
"That's what you should do. Don't teach Intelligent Design theory which is an alternative explanation. Simply teach the current mainstream explanation and the problems with that explanation, and leave it at that."
The problem, he says, is that evolution can't explain many aspects of nature including how the universe began.
Alan Leshner worries that undermining a fundamental theory of science threatens to weaken science teaching.
"We in the scientific community think we have an obligation to the young people of this country to prevent them from being poorly educated about science."
No matter what the outcome is in the Pennsylvania case, both sides agree, ultimately, it will be the Supreme Court that issues the final verdict.