The Dover Area School District on Monday was to start defending its policy of requiring 9th grade students to hear about "intelligent design" before biology lessons on evolution.
Dover is believed to be the first school system in the nation to require that students be exposed to the concept under a policy adopted by a 6-3 vote in October 2004.
Intelligent design, a concept some scholars have named and advanced over the past 15 years, holds that Charles Darwin's theory of natural selection cannot fully explain the origin of life or the emergence of highly complex life forms. It implies that life on Earth was the product of an unidentified intelligent force, therefore following creationist principles.
Critics say intelligent design is merely creationism — a literal reading of the Bible's story of creation — camouflaged in scientific language, and it does not belong in a science curriculum. Eight Dover families are suing the school district, alleging that the policy violates the constitutional separation of church and state.
"The intelligent-design movement is an effort to introduce creationism into the schools under a different name," said Eric Rothschild, a Philadelphia attorney representing the families.
And the debate in Dover has grown so intense that some students in this small town have decided to not put up with it.
"I opted out," a student named Haley told CBS News correspondent Thalia Assuras for The Early Show. "Why? Just because I don't feel it is right that it was put in science class."
The history of evolution litigation dates back to the 1925 Scopes Monkey Trial, in which Tennessee biology teacher John T. Scopes was fined $100 for violating a state law that forbade teaching evolution. The Tennessee Supreme Court reversed his conviction on the narrow ground that only a jury trial could impose a fine exceeding $50, and the law was repealed in 1967.
In 1968, the U.S. Supreme Court overturned an Arkansas state law banning the teaching of evolution. And in 1987, it ruled that states might not require public schools to balance evolution lessons by teaching creationism.
The clash over intelligent-design is evident far beyond this rural district of about 3,500 students 20 miles south of Harrisburg. President Bush has weighed in, saying schools should present both concepts when teaching about the origins of life.
In August, the Kansas Board of Education gave preliminary approval to science standards that allow intelligent design-style alternatives to be discussed alongside evolution.
And today, 11 Dover parents, including former Dover School Board member Barrie Callahan, are teaming up with the ACLU to sue the school board.
"It is absolutely wrong to change the definition of science by introducing God," Callahan told Assuras.
"What this is is a controversy surrounding the biological evolution and this is why it should be in the science class," Thompson said.
It requires teachers to read a statement that says intelligent design differs from Darwin's view and refers students to an intelligent-design textbook, "Of Pandas and People," for more information.
"All the Dover school board did was allow students to get a glimpse of a controversy that is really boiling over in the scientific community," Thompson said.
The Discovery Institute, a Seattle-based think tank that represents many scholars who support intelligent design, opposes mandating it in public schools. Nevertheless, it considers the Dover lawsuit an attempt to squelch voluntary debates over evolution.
"It's Scopes in reverse. They're going to get a gag order to be placed on teachers across the country," said institute senior fellow John West.
Eugenie Scott, executive director of the National Center for Science Education, which supports the teaching of evolution in public schools, said the controversy has little to do with science because mainstream scientists have rejected intelligent-design theory.
Intelligent design supporters "seem to have shifted virtually entirely to political and rhetorical efforts to sway the general public," Scott said. "The bitter truth is that there is no argument going on in the scientific community about whether evolution took place."