South Korean scientists have become the first to successfully clone a human embryo and harvest stem cells from it, a technique that could one day lead to replacing tissues to treat diseases such as diabetes and Parkinson's.

The South Korean scientists collected 242 eggs and were able to clone 30 early-stage embryos containing 100 cells. From those, they harvested one colony of stem cells.

Stem cells are unspecialized cells, meaning they can develop into many different cell types to form skin, bones, organs or other body parts. Doctors and scientists hope to take advantage of this property by using the cells to repair damaged tissue and to treat a variety of diseases.

Microscopic view of cell being manipulated

Previous attempts to clone human embryos have failed.

Details of the research will be published Friday in the journal Science.

An international controversy has erupted over whether to ban human cloning entirely, or to allow some form of therapeutic cloning. The U.S. has called for a ban on all human cloning. Britain is the only European country that would allow it.

Canada is one of the last countries in the world not to regulate this area.

The South Korean announcement comes at the same time as Paul Martin's government has reintroduced a bill that would ban human cloning and prohibit the sale of human sperm, eggs and embryos, but permit embryonic stem-cell research.

Some members of Parliament, including Liberals, are against the proposed bill that would allow for stem-cell research.

They say embryos are the beginning of life and should not be used for research.