You could, theoretically, take DNA from a paralyzed person, use it to grow an embryo of stem cells, then grow the stem cells into new nerve cells to put back into the person's spinal cord to end the paralysis. Unlike a transplant, these new cells would be from the same person and wouldn't get rejected by the body.

Been there, done that, got the stem cells
Something similar has been done in animals already. Researchers found that a paralyzed rat was able to move again after receiving stem cells in its spinal cord. In sheep, replacement nerve cells have cured spina bifida. Results like these sound encouraging, but there's a long road from animal studies to human therapies.

What the announcement meant
In November 2001 Advanced Cell Technology (ACT), a biotechnology company in Massachusetts, announced that it had been able to get human eggs to grow with inserted DNA. The eggs developed into little groups of cells called embryos, but did not live long enough to make stem cells.

Some scientists claim the announcement didn't mean anything because the experiment didn't work. "It's a complete failure," said Dr. George Seidel, a cloning expert at Colorado State University. Others believe that the research work ACT is pursuing, called therapeutic cloning, should be stopped. President Bush called the procedure "bad public policy--not only that, it's morally wrong in my opinion."

What's the outlook?
ACT researchers remain excited about the possibilities for the work they're doing. "Three thousand Americans die every day of diseases that therapeutic cloning could treat," said Robert Lanza, director of medical research at the company, in an interview. "It would be wrong of us to abandon those people because we're afraid of controversy." Jose Cibelli, one of the researchers responsible for the cloning work, stated in an interview, "Patients are all waiting for the public to get over the hype and fearfulness so that they have a chance to live."

At this point, no one can tell whether the success that researchers have had with stem cells in animals will be achieved in human stem cell research. And no one can tell whether therapeutic cloning will become what ACT thinks it will. Perhaps the United States will outlaw therapeutic cloning altogether. The old cliché applies: Only time will tell.

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