South Korean researchers say they have successfully cloned a human embryo and removed from it multipurpose cells called stem cells.
The experiment by Korean and U.S. scientists at Seoul National University is likely to reignite the controversy over human cloning. An article about their work appears in this week's edition of Science magazine.
A stem cell is a kind of master cell that can be used to grow any kind of tissue in the body. Supporters of stem cell research say it could lead to highly effective treatments for diseases ranging from Parkinson's to diabetes.
It could also allow patients to grow their own organs or tissue for transplantation. However, critics say the technique is unethical because it involves destroying a human embryo.
The eggs and cells used in the South Korean experiment were donated by South Korean women.
Scientists have cloned sheep, cattle, mice and other species. The Bush Administration has been spearheading efforts to ban human cloning -- both for the purpose of reproduction and for extracting stem cells.
Information for this report is provided by AP, AFP and Reuters.