What type of cloning?

Byline: The Register-Guard

Fortunately, a Massachusetts company's attempt to clone human embryos for use as stem-cell factories failed. The failure is fortunate because science has left public policy far behind, as evidenced by the varied reaction - alarm in some quarters, hope in others - to the cloning efforts. In its rush to catch up, public policy might veer off in the wrong direction, such as a ban on all types of human cloning.

The U.S. House of Representatives has already passed such a ban, as have four states. President Bush greeted Advanced Cell Technology's announcement of its research results by urging the U.S. Senate to do the same. Human cloning is "morally wrong," the president declared: "We should not, as a society, grow life to destroy it."

Destroying life, however, is not the aim of most medical research using cloning techniques. The aim is to save or improve lives. Treatments or cures for diabetes, Alzheimer's and other diseases might become available if researchers can find ways to grow healthy copies of sick people's cells. Using cells that are identical to a patient's own offers the promise of regenerating diseased or damaged tissue without the risk of rejection by the body's immune system.

Advanced Cell Technology's efforts fell far short of the goal of producing usable stem cells, some of which can develop into any cell type. In one experiment, the company implanted adult cells into human eggs. "With a little luck," company researchers wrote in Scientific American's online edition, "we hoped to coax the early embryos to divide into hollow spheres of 100 or so cells called blastocysts. We intended to isolate human stem cells from the blastocysts to use as starter stock for growing replacement nerve, muscle or other tissues that might one day be used to treat patients with a variety of diseases."

But cell division occurred in only a few of the embryos, and in no case progressed beyond six cells. The company had slightly greater success in prompting cell division in unfertilized human eggs, producing blastocysts through a process called parthenogenesis. This, the researchers wrote, showed that "the goal of therapeutic cloning is within reach."

Maybe so. But even if the company's hopes are realized, this work would be far removed from reproductive cloning, whose aim is to create replicas of an entire living organism. Reproductive cloning has been successfully attempted with animals, such as Dolly the sheep in 1997. Advanced Cell Technology's scientists oppose this type of cloning: "(W)e support a restriction on cloning for reproductive purposes until the safety and ethical issues surrounding it are resolved."

Such a resolution will require a clear scientific and legal distinction between therapeutic and reproductive cloning. The Senate needs to determine whether the distinction can be drawn before it joins the House in banning all human cloning research. Publicly funded research is already banned; a law against private research projects would criminalize a branch of science, forcing it to go underground or abroad.

In September, a committee of the National Academy of Sciences touched on the issue of therapeutic cloning in the course of reviewing the consequences of President Bush's limits on stem-cell research. Because human fetuses are the source of most stem cells, the research is opposed by anti-abortion groups and others who fear that human beings in their earliest stages of development might one day serve as stem-cell factories.

Noting that federal limits threaten to block or delay stem-cell research, the committee recommended "that scientists be allowed to pursue a controversial technique that can be used to create stem cells that are a genetic match to a patient. This method involves removing the nucleus of an egg call, replacing it with genetic material from the transplant patient, and triggering cell division. The method is controversial because it is similar to techniques used for reproductive cloning. However, unlike reproductive cloning, the resulting embryo will not be used to produce a child but rather to derive stem cells for the transplant patient."

That's exactly what Advanced Cell Technology tried to do. Another National Academy of Sciences panel is exploring the issues raised by human cloning and is expected to report early next year. The Senate should wait to see that report before deciding whether to join the House in voting for a complete ban on human cloning. There ought to be a way to stop scientists from creating cloned babies without closing an enormously promising avenue of medical research.