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KNOXVILLE, Tenn. — Cloning research may provide the best answer yet to the question of whether environment or genetics makes the greatest contribution to the growth and development of animals, a University of Tennessee medical ethicist said Wednesday.

Dr. Glenn Graber said the recent cloning of a sheep will spur new research that shows how clones can be very different from the life forms from which they are copied.

“Cloning is the definitive test of the old debate about whether genetics or environment makes the greater contribution to our being,” Graber said. “You may get a cow that is a fantastic milk producer, but if its clone is raised in another setting, with a different diet and other different conditions, it may not be nearly as good.

“I think we will find that environment makes a greater contribution than we realize, even to some things that may seem physical or genetic.”

Graber said studies have shown that identical twins and other genetically similar groups can grow to be distinctly different individuals.

Graber said most scientists oppose cloning humans because of ethical concerns. However, some people may seek human clones in the future, he said.

For example, parents might want to replace a lost child with a cloned one. Doing so would create serious psychological problems for the parents and the cloned child, Graber said.

“In grief counseling, one of the worst reasons to have another child is to see it as a replacement,” Graber said. “It stops parents from grieving properly and creates problems in the child.

“There would be too much pressure on a cloned child to be like the one that was lost, and it may not be exactly the same. The problems would outweigh the benefits.”

Contact: Dr. Glenn Graber (423-974-7213)