In recent years, voters, educators and policymakers in a number of states have become involved in the debate over whether - or how - public school students should learn about evolution and the origins of life. The debate has taken place at various levels of state government, from legislatures to local school boards. In some states and localities, evolution opponents argue for academic freedom in an effort to grant teachers and students the right to question evolutionary theory. Supporters of teaching evolution counter that such efforts could replace science with religiously based notions in the classroom. What follows is a sampling of recent action in 14 states in which the teaching of evolution has stirred controversy.

Alabama 

In November 1995, Alabama's Board of Education voted to place stickers on public school biology textbooks instructing high school students that evolution was "a controversial theory" and that "any statement about life's origins should be considered as theory, not fact." In November 2001, the language on the sticker was revised. The new language instructs students to "learn to make distinctions between the multiple meanings of evolution" and "to wrestle with the unanswered questions and unresolved problems still faced by evolutionary theory."

Arkansas 

In January 2005, the American Civil Liberties Union (ACLU) demanded that the Beebe, Ark., school board remove stickers placed on public school biology textbooks questioning evolutionary theory and introducing the concept of "an intelligent designer." The stickers had been adopted in the 1990s but had elicited no complaints until the ACLU drew attention to them in 2005. In July 2005, the Beebe school board decided to remove the stickers after the ACLU threatened a lawsuit and after a federal judge ruled against similar stickers that were being used in Cobb County, Ga. (See below.)

Florida 

In February 2008, Florida's Board of Education revised its 12-year-old state science standards to require the teaching of evolution for the first time. The updated Florida guidelines also state that "natural selection is a primary mechanism leading to evolutionary change" and that "the scientific theory of evolution is the fundamental concept underlying all of biology." These changes are considered a victory for supporters of Darwin's theory. However, the consistent use of the phrase "the scientific theory of evolution" rather than simply "evolution" troubled some evolution supporters, who argued that the word "theory" could be mistaken to mean a mere hunch rather than a tested explanation for a natural phenomenon.

Georgia 

In 2002, after receiving a petition signed by more than 2,000 parents complaining that alternative theories to evolution were not being presented in public school science textbooks, the school board in Cobb County, Ga., placed stickers on biology textbooks instructing students that "evolution is a theory, not a fact, regarding the origin of living things." In January 2005, a federal judge ruled that the stickers were unconstitutional because they had the effect of endorsing a religious viewpoint. The county school board removed the stickers but appealed the ruling. In December 2006, following a settlement with the ACLU, the school board withdrew its appeal.

Kansas 

The teaching of evolution in Kansas has been the subject of a long and contentious debate; indeed, the state's Board of Education has rewritten its science education guidelines on four separate occasions since 1999. The latest change came in February 2007, when a new board voted to remove language that questioned the theory of evolution and included a controversial definition of science. The new standards require students to learn about evolution through natural selection and state that "biological evolution is used as a broad, unifying theoretical framework for biology." Although the board's science guidelines are used to draft the content of state exams, they do not determine what specifically is taught in local public school science classrooms.

Kentucky 

According to a Kentucky state law passed in 1976 and re-adopted in 1990, public school teachers who teach evolution may also teach "the theory of creation as presented in the Bible." Although this law has not been challenged in court, reports vary over the extent to which creationism is actually taught in public schools. In 1998, the Kentucky Board of Education voted to insert the word "evolution" for the first time into the state science curriculum guidelines. But just a year later, the board replaced "evolution" with the phrase "change over time." This language remains in effect.

Louisiana 

In 1981, the Louisiana Legislature passed the Louisiana Balanced Treatment Act, which stipulated that whenever evolution was taught in a public school science classroom, creation science must be taught alongside it. In Edwards v. Aguillard (1987), the U.S. Supreme Court ruled that this law had a religious purpose and thus violated the Establishment Clause in the First Amendment to the U.S. Constitution. In June 2008, Louisiana Gov. Bobby Jindal signed into law the Louisiana Science Education Act, which allows public school teachers and school boards to provide supplemental educational materials that "help students understand, analyze, critique, and review scientific theories in an objective manner." The implementation of this policy is the subject of ongoing debate and threats of legal action.

Michigan 

In October 2006, the Michigan Board of Education voted unanimously to pass new state science standards that ensure the teaching of evolution but not the teaching of intelligent design or creation science. Language that some educators had argued cast doubt on the theory of evolution was removed from the final version of the guidelines. The new standards require public school students to be able to "explain how a new species or variety originates through the evolutionary process of natural selection" and "how the fossil record, comparative anatomy, and other evidence supports the theory of evolution."

New Mexico 

In August 2005, the school board in Rio Rancho, N.M., passed a science policy that allowed teachers and students to discuss alternative theories to evolution and to "acknowledge that reasonable people may disagree about the meaning and interpretation of data." The policy prompted criticism from teachers and the ACLU. In April 2006, borrowing language from state science standards, the Rio Rancho school board amended this policy to say that "students shall understand that reasonable people may disagree about some issues that are of interest to both science and religion." Still, after threats of legal action and continued controversy over the purpose of the policy, the school board rescinded the policy in December 2007.

Ohio 

In December 2002, the Ohio Board of Education revised its high school science standards to include the word "evolution" for the first time in 77 years. While the standards did not require that intelligent design be taught or tested in classrooms, they did mandate that 10th grade science students understand "how scientists continue to investigate and critically analyze aspects of evolutionary theory." In March 2004, the board approved a model lesson plan for 10th graders titled "Critical Analysis of Evolution." In February 2006, however, the board rescinded both the critical analysis requirement and the lesson plan following a 2005 federal court ruling in Dover, Penn., striking down the teaching of intelligent design. (See below.)

Pennsylvania 

In October 2004, the Dover, Pa., school board inserted an oral disclaimer into its 9th grade biology curriculum that included brief instruction in intelligent design. A group of parents represented by the ACLU filed a lawsuit against the school board, claiming that the policy violated the First Amendment's Establishment Clause. In December 2005, a federal judge ruled in favor of the parents, describing intelligent design as "a religious view, a mere re-labeling of creationism, and not a scientific theory." In January 2006, a newly elected Dover school board unanimously rescinded the intelligent design disclaimer.

South Carolina 

In June 2006, state officials approved new science standards requiring high school students to "summarize ways that scientists use data from a variety of sources to investigate and critically analyze aspects of evolutionary theory." While this change was heralded by intelligent design proponents, critics of the guidelines argue that they might allow religion to be taught in public school science classrooms.

Texas 

The Texas Board of Education is currently revising its science curriculum, which was last approved in 1998. The current curriculum states that students should analyze and critique the "strengths and weaknesses" of scientific theories such as evolution. The proposed new guidelines remove the "strengths and weaknesses" language, which has been in place since 1988, and state that "scientific theories are well-established and highly reliable explanations, but may be subject to change as new areas of science and new technologies are developed." The board is expected to conduct a final vote on this new language in March 2009. The battle in Texas is considered important, since the state is the second-largest purchaser of public school textbooks in the country, and its education standards can influence how textbook publishers treat certain subjects.

Wisconsin 

In October 2004, the Grantsburg, Wis., school board became the first in the nation to allow the teaching of "various theories/models of origins" in its public school science curriculum. In response to concerns that the policy allowed the teaching of intelligent design and creation science, however, the school board revised the guidelines in December 2004 to state that "students shall be able to explain the scientific strengths and weaknesses of evolutionary theory. This policy does not call for the teaching of creationism or intelligent design." While Wisconsin public schools are required by state law to teach evolution, district schools may determine the specifics of their own science curricula.

This report was written by Michelle Ralston, a research assistant at the Pew Research Center's Forum on Religion & Public Life.