US scientists claim to have cloned the first human embryo. It is a major scientific breakthrough. At the same time it has rekindled one of the most emotionally-charged debates of our time.
Dolly: the sheep that could change our lives
The breakthrough was achieved by researchers of Advanced Cell Technology, based in Massachusetts, USA. On Sunday they announced that they had succeeded in creating the first cloned human embryos.
Their experiments could be a major step forward in developing a made-to-measure repair kit of human tissue, cultivated in a lab from one’s own genetic material.
The aim of therapeutic cloning is to take a piece of skin and grow a new heart for a heart patient, or brain tissue for an Alzheimer's patient, or vital pancreatic cells for a diabetes patient.
But the announcement also quickly drew criticism from those fearing the step would lead to the cloning of a human being.
Pro-life campaigners were quick to describe the experiments as horrific. Cloning research that deliberately created then destroyed human embryos was abhorrent, they said.
A key to healing?
Dr Robert Lanza, vice president of medical and scientific development at ACT, said: "Our intention is not to create cloned human beings.
"Rather it is to make lifesaving therapies for a wide range of human disease conditions, including diabetes, strokes, cancer, Aids and neuro-degenerative disorders such as Parkinson's and Alzheimer's disease."
The ACT team said it created the embryo using the same technique that was used for Dolly the sheep.
It first scraped out the DNA from a human egg cell, then injected it with the nucleus from a human skin cell and finally kick-started the egg with electricity.
Crossing the line
Animals have been cloned repeatedly since Dolly the sheep made her appearance in 1997 and there were no real technical barriers to making a cloned human embryo.
But the research crosses a line that has left many people across the board uneasy and even hostile.
The critics of embryo research include the White House. President George W. Bush condemned the research.
"The use of embryos to clone is wrong," he told reporters. "We should not as a society grow life to destroy it. And that's exactly what's taking place."
Richard Armey,a Texas Republican, said "It's time for the Senate to put the deal-making aside and join the House in banning human cloning before it's too late."
He has the backing of anti-abortion groups, many of which also oppose embryonic stem cell research.
Cloning experts last night stressed that the findings were "preliminary" and that the company had yet to prove it had created a clone.
Ian Wilmut, of the Roslin Institute in Edinburgh, who cloned Dolly the sheep, urged caution over the announcement. Because unfertilised eggs could divide spontaneously, the "embryos" might not have been clones, he said.
The Vatican expressed caution and reservation, saying that further scientific verification was necessary. If a real embryo was created, then destroyed, "that must be condemned", said a spokesman.