First human embryo cloned

Scientists have successfully cloned 30 human embryos in an astonishing breakthrough.

They believe their work could lead to a cure for diseases such as cancer and Parkinson's. But experts warned it could also open the door for the first cloned human baby.

Scientists from Seoul National University took genetic material from normal cells in women donors and combined it with their eggs. They grew embryos to a point at which stem cells - the body's "master cells" that can divide into any type of tissue in the body - developed. The embryos were then destroyed to harvest the stem cells.

"These are the most advanced human embryo clones yet produced," said Professor Woo Suk Hwang, the doctor behind the research. But he said any attempt to create a cloned baby would be "crazy".

The scientists' aim is to use the stem cells to grow replacements for cells that have failed in patients with problems such as Alzheimer's disease. Because the cells are an exact genetic match with those of the donor, it is thought the body will not reject them.

"Our approach opens the door for the use of these specially developed cells in transplantation medicine," said Professor Hwang.

The breakthrough is the first time claims of a cloned human embryo have been backed up by a scientific evidence. A paper detailing the research will appear this week in the journal Science. However, anticloning campaigners in America have already condemned the research. It was described last night as "a move towards creating new human lives solely to destroy them in research," by a senior member of the United States Conference of Catholic Bishops.

Another opponent of cloning, Dr Leon Kass of the President's Council on Bioethics, warned: "The age of human cloning has arrived."

Experts stressed that the research is still at an early stage. Editor-in-chief of the journal Science, Donald Kennedy, said: "The potential for embryonic stem cells is enormous - but researchers still must overcome significant scientific hurdles.

"These results seem promising. But it's important to remember that cell-and-tissue transplantation and gene therapy are still emerging technologies, and it may be years yet before embryonic stem cells can be used in transplantation medicine."

He also called for a worldwide ban on attempts to use the technology to create living children. One US company claimed that, by publishing their work, the Korean scientists were making it easy for others to copy it.