South Korean scientists claim that they have cloned several human embryos and extracted valuable stem cells from one, and said their achievement showed an immediate need for a global ban on cloning to make babies.
They are the first researchers to prove they cloned a human embryo and said they did it not to make a baby but for therapeutic purpose.
It is "an alarming development" in the field of medical science, researchers say.
It could eventually involve taking a plug of skin from a patient and using it to grow perfectly matched tissue or even organs to treat diseases ranging from diabetes to Alzheimer's.
It was clearly wrong to use the technique for making an embryo that would be put into a woman's womb to grow into a baby.
We call for a ban on reproductive cloning and for preventing reproductive cloning we would like to ask every country or nation to have a law to prohibit reproductive cloning.
To clone a human being is to move from procreation to manufacture of human life. If human beings are special, if human beings are truly sacred, then we must devote ourselves to a better world. But we must not do evil to bring about good.
It was time for lawmakers around the world to agree on what to do about cloning. No religion, no moral authority can claim to be the final arbiter of this work.
Scientists welcomed the work as a breakthrough but stressed it would be years before any patient benefited from this new technique.
I point out that it is long-range, not short-range promise. If it turns out true, it's a nice step forward.