WASHINGTON -- President Bush waded into the debate over evolution and ''intelligent design" yesterday, saying schools should teach both theories on the creation and complexity of life.

In a wide-ranging question-and-answer session with a small group of reporters, Bush essentially endorsed efforts by Christian conservatives to give intelligent design equal standing with the theory of evolution in the nation's schools.

On other topics, Bush said he has no idea how Supreme Court nominee John G. Roberts Jr. would vote in a case challenging the legality of abortion because he never asked him about it. He also defended Baltimore Orioles first baseman Rafael Palmeiro, who was suspended yesterday for using performance-enhancing steroids.

Bush declined to state his personal views on ''intelligent design," the belief that life forms are so complex that their creation cannot be explained by Darwinian evolutionary theory alone, but rather points to intentional creation, presumably divine.

The theory of evolution, first articulated by British naturalist Charles Darwin in 1859, is based on the idea that life organisms developed over time through random mutations and factors in nature that favored certain traits that helped species survive.

Scientists concede that evolution does not answer every question about the creation of life, but most consider intelligent design an attempt to inject religion into science courses.

Bush compared the current debate to earlier disputes over ''creationism," a related view that adheres more closely to biblical explanations. As governor of Texas, Bush said students should be exposed to both creationism and evolution.

The president said yesterday that he favors the same approach for intelligent design ''so people can understand what the debate is about."

The Kansas Board of Education is considering changes to encourage the teaching of intelligent design in Kansas schools, and Christian conservatives are pushing for similar changes in other school districts across the country.

''I think that part of education is to expose people to different schools of thought," Bush said. ''You're asking me whether or not people ought to be exposed to different ideas, the answer is yes."

The National Academy of Sciences and the American Association for the Advancement of Science have both concluded that there is no scientific basis for intelligent design and oppose its inclusion in school science classes.

''The claim that equity demands balanced treatment of evolutionary theory and special creation in science classrooms reflects a misunderstanding of what science is and how it is conducted," the academy said in a 1999 assessment. ''Creationism, intelligent design, and other claims of supernatural intervention in the origin of life or of species are not science because they are not testable by the methods of science."

Some scientists have declined to join the debate, fearing that amplifying the discussion only gives intelligent design more legitimacy.

Bush was more than ready for questions about his Supreme Court nominee. Bush said he deliberately avoided discussing Roe v. Wade, the 1973 ruling that legalized abortion nationwide, with Roberts before selecting him for a spot on the nation's highest court.

The president said he was concerned that if Roberts expressed an opinion, he would have to withdraw from any case challenging the landmark decision.

He also said he believed Palmeiro when he testified that he didn't use steroids. Palmeiro is Bush's friend from their days together with the Texas Rangers in the early 1990s.

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