Usually, embryonic stem cells are derived from embryos that have grown into 100-cell balls that are smaller than a pinhead. Lanza's technique starts earlier, when embryos are just ten-cell clusters. His group showed that one of these cells can be used to create embryonic stem cells, potentially without destroying the embryo from which it was taken. "The embryos are like a bunch of grapes," Lanza says, "and you pluck one out."

This "plucking out" is actually already used in some in vitro fertilization as part of a technique called pre-implantation diagnosis, which allows prospective parents to screen out embryos with a serious genetic flaw. That technique has created healthy babies. Researchers, including those at Advanced Cell, say that right now, it would only be ethical to use the new stem-cell creation technique in cases where such testing was being used.

Other scientists say that the new technique needs to be repeated by other groups before it can be believed, and that its efficiency needs to be improved. "It is premature to argue that this can replace current techniques of stem cell derivation," says Martin Pera, a stem cell researcher at the University of Southern California.

Lanza and his team did destroy many of the embryos used in their tests, because they went back often to the same embryo, taking more than a single cell. Lanza says he did not want to destroy many embryos in a proof-of-concept experiment. Already, research for the paper resulted in 19 new embryonic stem cell lines.

Another caution comes from researchers still stung by a paper in Science from Korean researchers that purported to show another stem cell advance and turned out to be fraudulent.

"This field has had its fair share of disappointments," says Arnold Kriegstein, head of the Institute for Regenerative Medicine at UC-San Francisco. "We have to temper our enthusiasm until this has had a chance to be tried in other hands." However, he adds, "The data I saw in the paper looked quite convincing."

For Advanced Cell Technology, the paper represents another controversial result among many. The firm was long guided by Michael West, who as chief executive of Geron

funded the creation of the first human embryonic stem cells in 1998. West went to Advanced Cell to continue that work, and the company has become known for scientific work that directly confronts the ethical problems inherent in stem cell research and cloning. That has not resulted in much money or venture capital. There were times when the firm had trouble paying its phone bill.

"We're going by seat of the pants here, but my feeling is that this is a great breakthrough," says Ronald Green, the Dartmouth professor who heads the ethics review board for Advanced Cell, a position for which he makes $200 a year. If put into use only with embryos used in pre-implantation diagnosis, the new technique could create dozens of new stem cell lines every year, he says.

"It's very unusual for science to resolve our ethical debates," says Green. "In most cases, science complicates them. This is one of those unusual circumstances where I think the science may have resolved an ethical quandary."

Source Forbes