Associated Press

Michael D. West, president and chief executive officer of Advanced Cell Technology, stands in a lab in this Dec. 20, 1998 file photo in Worcester, Mass. In a paper published yesterday in the Journal of Regenerative Medicine, ACT announced that it had successfully performed somatic cell nuclear transfer (cloning) to form human preimplantation embryos.

BOSTON - A group of scientists in Massachusetts claimed yesterday they had cloned the first early human embryo, a step toward providing genetically matched replacement cells for patients with a wide range of diseases.

The scientists at Advanced Cell Technology, in Worcester, Mass., say they have no interest at present in transplanting such early embryos into a woman's womb to give birth to a cloned human being.

Several states, including California, have banned human cloning. Congress is considering such a ban.

"These are exciting preliminary results," said Dr. Robert P. Lanza, one of the researchers at Advanced Cell Technology. "This work sets the stage for human therapeutic cloning as a potentially limitless source of immune-compatible cells for tissue engineering and transplantation medicine."

In findings published yesterday by The Journal of Regenerative Medicine and described online in Scientific American, the scientists said they had grown a six-cell human embryo.

They said they created the early embryo by injecting a very small cell with its genetic material into a woman's donated egg. In such cloning, the injected DNA often comes from a skin cell, but the researchers this time used a cumulus cell, which nurtures a developing egg.

In a separate experiment, the scientists showed they could push the development of human egg cells even further with a technique known as parthenogenesis.

They exposed 22 egg cells to chemicals that changed the concentration of electrically charged ions within them. Six eggs reprogrammed themselves to develop into early embryos known as blastocysts, which contain dozens of cells.

The scientists described the work as preliminary. Neither experiment has yet produced the coveted stems cells that grow inside an embryo and differentiate into other body tissues.

But the researchers described the work as an important step toward producing these stem cells to generate replacement cells as treatments for diabetes, heart disease, spinal injuries, and many other ailments.

Asked about the research on "Fox News Sunday," Senate Majority Leader Tom Daschle, D-S.D., said while he only had sketchy details, he was worried about reproductive cloning. He called the reports "disconcerting."

"I think it's going in the wrong direction," he said.

On NBC's "Meet the Press," Sen. Richard Shelby, D-Ala., said "I believe it will be perhaps a big debate, but at the end of the day I don't believe that we're going to let the cloning of human embryos go on."

Added Sen. Patrick Leahy, D-Vt.: "I find it very, very troubling."

Sen. Richard Lugar, R-Ind., told CNN's "Late Edition" that "the Senate should be deliberative."

"We really ought to take it on the basis of much more thorough understanding than this first report," he said.