WASHINGTON D.C. -- The death of Dolly the sheep, the world's first cloned mammal, should serve as a warning to those who seek to clone human beings, Southern Baptist ethicists say.

According to Baptist Press, Dolly was put to death after being diagnosed with a progressive lung disease. The diagnosis may be another piece of evidence that the 6-year-old sheep was showing signs of advanced aging. Sheep routinely live to be 11 or 12.

In 1999, researchers found Dolly's cells had begun to resemble those more typical of an older mammal, and she began to develop signs of arthritis.

"Apparently while Dolly was chronologically 6, her genes were manifesting the abnormal age of the mammal from which she was cloned," said Richard Land, president of the Southern Baptist Ethics & Religious Liberty Commission (ERLC). Dolly's fate "is yet one more compelling reason for why we should not be allowing this kind of experimentation on human beings. It will lead to pain, agony, disfigurement and death."

Ben Mitchell, a consultant for the ERLC and a bioethics professor at Trinity Evangelical Divinity School in suburban Chicago, said, "To subject a sheep to the consequences of cloning was cruel; to subject a human being to those consequences is criminal. And our laws should reflect that fact."

Even one of the collaborators on Dolly's cloning said her Feb. 14 death is a warning.

"I think it highlights more than ever the foolishness of those who want to legalize [human] reproductive cloning," said Alan Colman, who now is a researcher in Singapore, according to an Associated Press report. "In the case of humans, it would be scandalous to go ahead given our knowledge about the long-term effects of cloning."

While other animals since Dolly have been cloned, many attempts have failed. Some efforts have resulted in deformed and still-born fetuses. Other abnormally sized clones have died shortly after birth, the AP reported.

Dolly was born only after more than 270 failed attempts.