Pope John Paul II (search) warned in a statement released Sunday that humanity's speedy progress in science and technology risks overlooking moral values, citing with particular concern experiments in human cloning.

The pontiff — in a message written Aug. 6 but released Sunday for the start of a Church-organized meeting on the theme of progress — insisted that advanced research must not become an end in itself.

"The results achieved in various fields of science and technology are considered and defended by many as a priori acceptable," he said. "In this way, one ends up expecting that what is technically possible is in itself also ethically good."

The pontiff continued: "There is no one who does not see the dramatic and distressing consequences of such pragmatism, which perceives truth and justice as something modeled around the work of man himself. It is sufficient, as one example among others, to consider man's attempt to appropriate the sources of life through experiments in human cloning (search)."

John Paul cited this as an example of "the violence with which man tries to appropriate the truth and the just, reducing them to values that he can dispose of freely, that is, without recognizing limits of any kind if not those fixed and continually overcome by technological possibility."

The pope has issued condemnations of cloning in the past. At his visit a week ago to the French shrine of Lourdes, he urged that life be "respected from conception to its natural end."

Fresh debate over cloning was sparked Aug. 11 when Britain granted its first license for human cloning for stem cell research (search). The license went to researchers who hope eventually to create insulin-producing cells that could be transplanted into diabetics.

Many scientists believe stem cells hold vast promise for treating an array of diseases. Stem cells can potentially grow into any type of human tissue and scientists hope to be able to direct the blank cells to grow into specific cell types needed for transplant.