What's in a name? When it comes to controversial science, a lot.

South Korean scientists recently announced they had used cloning to produce 11 human embryos and destroyed them to harvest their embryonic stem cells. Actually, they said they had used "somatic cell nuclear transfer" to produce "human NT blastocysts," from which they extracted "hESC" (for human embryonic stem-cell lines).

In fact, nowhere in their paper did they use the word "clone."

"Everybody is terrified of the word, 'cloning' " said Dr. David Shaywitz, a stem-cell researcher at Harvard University. "It conjures up so many frightening images.

"Both sides are trying to manipulate language. People who are opposed to the research go out of their way to use that word, and people who support the research are trying to find other ways to explain what they are doing."

But cloning opponents are disturbed by the way stem-cell scientists these days almost always speak of "somatic cell nuclear transfer" rather than "cloning."

"The most important thing to be said is that the language is changing, and it seems to have an agenda behind it to make things more acceptable," said Dr. John Kilner, the president for the Center for Bioethics and Human Dignity, which opposes cloning and destroying human embryos to extract their stem cells.

"I'm concerned," he added. "People ought to debate the scientific issues on the merits."

The word "embryo" presents similar problems. The South Korean scientists, for example, did not get their cloned embryos by fertilizing human eggs. Rather, they removed the genetic material from donated eggs and replaced it with genetic material from the cells of patients. Those new genes took over and directed the eggs to grow and divide. So, they said, the resulting balls of cells should be called "nuclear-transfer constructs."

But avoiding the term "embryo" merely "avoids a moral question that is very much in the public consciousness," said Dr. Lisa Cahill, a theology professor at Boston College. After all, she said, those balls of cells, however created, can develop and, if implanted in a womb, could in theory become babies. Those who oppose such research say the embryos are human, and they object to destroying human life.

Early stages

Many scientists counter that embryos in their early stages, whatever their potential, are simply tiny clumps of undifferentiated cells — no budding organs or extremities, nothing remotely mammalian or babylike — and that they have no moral status.

Most Americans, Cahill said, occupy a position somewhere in between. They do not want to lose the promise of stem-cell research, but they also do not consider human embryos to be simply balls of cells.

This view, Cahill said, is "reflected in the fact that we've had the National Bioethics Council and the President's Council on Bioethics and a statement from the American Fertility Society all saying special respect was owed the embryo. But they didn't necessarily say that therefore it could never be used in research."

There is the further question of using cloning to create embryos. Should the word "clone" even be used if the embryos will never be allowed to develop into babies?

The International Society for Stem Cell Research wrestled with the issue and decided to use different words to distinguish between cloning to create embryos for their stem cells and to create babies.

The group decided that cloning to create embryos to the blastocyst stage, that critical time at about five days when stem cells can be obtained, and then destroying them to extract stem cells would be called "somatic cell nuclear transfer."

That term, said Gordon Keller, a stem-cell researcher at Mount Sinai School of Medicine in New York and the president-elect of the International Society for Stem Cell Research, accurately describes the process by which the blastocysts were made.

The other possible outcome for the blastocysts, something Keller said the society vehemently opposes, would be to implant them in a uterus to start a pregnancy. That would be called "cloning."

"The process is the same," Keller said. The important difference, he said, is "what you do with the blastocyst."

Council's conclusion

The president's Council on Bioethics unanimously came to a different conclusion about what to call the process of creating these blastocysts. "Although as a scientific matter 'somatic cell nuclear transfer' or 'nuclear transplantation' may accurately describe the technique that is used to produce the embryonic clone, these terms fail to convey the nature of the deed itself, and they hide its human significance," the council wrote.

Dr. Leon Kass, the council's chairman, said last week that the South Koreans' feat should not be disguised by jargon.

"The initial product of their cloning technique is without doubt a living cloned human embryo, the functional equivalent of a fertilized egg," Kass wrote in an e-mail message.

"If we are properly to evaluate the ethics of this research and where it might lead," he continued, "we must call things by their right names and not disguise what is going on with euphemism or misleading nomenclature."

A stem-cell researcher at Harvard University