BOB BAUM/AP Sports Writer

TEMPE, Ariz. (AP) _ Arizona Cardinals quarterback Kurt Warner says his deep Christian faith led to his decision to appear in a television ad opposing a proposed constitutional amendment in Missouri.

Warner, who led the St. Louis Rams to two Super Bowls and remains a highly popular figure there, joined St. Louis Cardinals pitcher Jeff Suppan, among others, in the television spot against Missouri's Amendment 2.

The amendment would change the Missouri constitution to guarantee the use of any federally allowed stem cell research and treatments, including work on human embryos. The possible use of embryonic stem cells and concerns about potential human cloning led to Warner's decision, he said.

He equates the use of an embryonic stem cell for research to taking a human life.

``I am all for finding a cure for any and every disease known to man,'' Warner said in an interview with The Associated Press after the Cardinals practiced on Thursday, ``but there are certain issues that outweigh just finding a cure and doing research, and life is one of those.

``I think life is too sacred to ever take it in any circumstances, even for the cure of a disease or something like that.''

The amendment is at the center of the critical race for the U.S. Senate in Missouri. Democrat Claire McCaskill supports the amendment and Republican incumbent Jim Talent opposes it.

Actor Michael J. Fox, who has Parkinson's disease, has appeared in an advertisement in support McCaskill, citing the need for stem cell research as he plainly exhibits the effects of the disease.

Warner said he has not seen the Fox ad, and said he supports adult stem cell research. But he said that even in cases where embryos are not going to be allowed to develop, they should not be used for research.

``To pass an amendment that allows for the opportunity to abort and to kill a life to me makes no sense,'' he said. ``It contradicts everything I believe, everything that I stand for and I think everything that Missouri stands for.''

Warner said he believed the ads promoting the amendment are deceptive because they fail to distinguish between adult stem cell research and that involving human embryos.

``This amendment also takes into considering embryonic stem cell research, which then becomes a pro-life issue,'' he said. ``It becomes aborting after conception, aborting fetuses, using for research purposes. It also has do to with the fertilization of eggs for the sole purpose of killing them and doing research.''

Warner said he was contacted by anti-amendment people to do the ad.

``I still feel a heavy responsibility for the people of Missouri because of the respect they have for me but also the things they've done for me,'' he said, ``and I don't want them to make an uninformed decision on something that can change their constitution in the long term and can have lasting effects not only in the state but I think also nationally.''