South Korea scientists report that they have created human embryos through cloning and extracted embryonic stem cells.

The development is what patients with diseases like Parkinson’s and diabetes had been waiting for, the start of so-called therapeutic cloning. The idea is to clone a patients cells to make embryonic stem cells that are an exact genetic match of the patient. Then those cells, patients hope, could be turned into replacement tissue to treat or cure their disease without provoking rejection from the body’s immune system.

However, the detailed description, reported in the Feb. 13 Science magazine, also makes the birth of a cloned baby suddenly more feasible. So it is likely to reignite the fierce debate over the ethics of human cloning.