ATLANTA — A federal judge yesterday ordered a suburban Atlanta school system to remove stickers from its high-school biology textbooks that call evolution "a theory, not a fact," saying the disclaimers are an unconstitutional endorsement of religion.

"By denigrating evolution, the school board appears to be endorsing the well-known prevailing alternative theory, creationism or variations thereof, even though the sticker does not specifically reference any alternative theories," U.S. District Judge Clarence Cooper said.

The stickers were put inside the books' front covers by public-school officials in Cobb County in 2002. They read: "This textbook contains material on evolution. Evolution is a theory, not a fact, regarding the origin of living things. This material should be approached with an open mind, studied carefully and critically considered."

"This is a great day for Cobb County students," said Michael Manely, an attorney for parents who sued over the stickers. "They're going to be permitted to learn science unadulterated by religious dogma."

The school board expressed disappointment and said it may appeal. A board spokesman said no decision had been made on when, or if, the stickers would be removed.

The stickers were added after more than 2,000 parents complained that the textbooks presented evolution as fact, without mentioning rival ideas about the beginnings of life, such as the biblical story of creation.

Six parents and the American Civil Liberties Union then sued, contending the disclaimers violated the separation of church and state and unfairly singled out evolution from thousands of other scientific theories as suspect.

The school system defended the stickers at trial as a show of tolerance, not religious activism.

"Science and religion are related, and they're not mutually exclusive," school-district attorney Linwood Gunn said. "This sticker was an effort to get past that conflict and to teach good science."