Scientists square off over stem-cell research

JEFFERSON CITY, Mo. -- Two medical scientists squared off Thursday over whether embryonic stem-cell research should be protected in Missouri's constitution, highlighting how even some experts disagree on an issue that less-knowledgeable voters likely will be asked to decide.

The key point of contention is whether human life is destroyed in a procedure that combines a patient's own DNA with a woman's egg, stimulates it to start growing, and then removes its stem cells for research or potential medical treatments.

A measure proposed for the November ballot would allow the procedure, so long as scientists do not try to implant the resulting embryo into a woman's uterus, where it theoretically could grow into a cloned baby.

But opponents contend the procedure -- known scientifically as somatic cell nuclear transfer -- results in the creation and destruction of human life in its earliest form. They want it banned.

Taking the supportive view Thursday was Steven Teitelbaum, a professor of pathology and immunology at Washington University in St. Louis. Opposing him was his university colleague Richard Chole, a professor of molecular biology and pharmacology.

The scientific debate sponsored by The Associated Press and the Missouri Press Association was the first of the year on the topic at the Missouri Capitol, where legislators are shying away from the debate in deference to the proposed ballot measure.

Stem cells are sometimes called the building blocks of life because they continuously divide and replenish themselves and can develop into cells with a variety of specialized functions -- forming the heart, lungs, skin, nervous system and other body parts.

Teitelbaum said he has successfully used stem cells taken from adults to treat diseases. But he said stem cells taken from embryos hold greater potential, because they have the ability to develop into a wider variety of body cells. He is hopeful that embryonic stem cells could help treat such ailments as Parkinson's disease, diabetes and certain heart problems.

But Chole said removing stem cells from an embryo -- regardless of how it was created -- kills what he considers to be a person.

"An embryo is one of the earliest forms of a living human being," Chole said.

Teitelbaum said that's an ethical decision that researchers and voters must make individually, not a scientific fact.

Chole noted that embryos created by somatic cell nuclear transfer have the same number of chromosomes as those created through the traditional joining of sperm and egg. And the procedure was used successfully several years ago to create Dolly the cloned sheep.

But when embryos are created through the cloning procedure, Teitelbaum said, some developmental genes don't activate as they do with sexual fertilization.

An embryo formed through sperm and egg successfully implants in a uterus one-third to one-half of the time, but it took 256 tries to create Dolly the sheep, he said. And the procedure has not yet been able to create a baby monkey, a primate more closely related to humans, Teitelbaum said.

"It is probably not possible to make a baby this way," he said.

Teitelbaum supports the ballot measure's language outlawing human cloning, which it defines as occurring when an embryo not created by sperm and egg is implanted into a woman.

But Chole said that definition is deceptive. He said the ballot measure actually allows human cloning, which he said has traditionally been understood as occurring the moment a scientifically created egg starts dividing.