South Koreans Extract Stem Cells from Cloned Human Embryo.

"Cloning is at present as much an art as a science. The success rate is very low. What really gave the Korean team an edge was that they were able to obtain 242 human eggs from 16 women volunteers who took hormone treatment to stimulate egg production. An ethics committee in the West might have questioned this, as the women themselves got no benefit. An American or European team would be lucky to get 20 eggs, as they are in short supply for IVF treatments, never mind `blue skies' research."

Nigel Hawkes, London Times

"The Korean scientists, if their experiment is confirmed in other laboratories, will have proved, in principle, the viability of the first step in therapeutic cloning, that of converting an ordinary body cell back into the embryonic state. But one element in their success is simply that they were able to amass enough human eggs to get the standard techniques to work, and had no legal restrictions standing in their way."

Nicholas Wade, New York Times

A team of South Korean researchers reported in the February 13 issue of the journal Science that it had created a cloned human embryo from which it derived stem cells. Cardinal William Keeler, chairman of the Committee for Pro-Life Activities of the United States Conference of Catholic Bishops, said this use of cloning to create and destroy human embryos "is a sign of moral regress."

The loss in human life was much more extensive than most press reports suggest. Using the 242 human eggs, the team of veterinary cloning expert Hwang Woo Suk and gynecologist Moon Shin Youg made 213 embryos at the two-celled stage. Forty survived to the "compacted morula" stage (3-4 days), then 30 to the blastocyst stage (5-7 days). From this the researchers were able to get inner cell masses from 20, but established a stable stem cell line from only one.

Hwang and Moon, both researchers at Seoul National University, argued that they were not intending to produce a baby (so-called "reproductive cloning") but (eventually) tailor-made replacement cells to assume the duties of cells damaged by disease (typically called "therapeutic" or "research" cloning). The theory is that some stem cells taken from human embryos can be coaxed into becoming almost any type of cell in the body.