Officials from 17 countries gathered here yesterday to sign the first agreement to ban human cloning, less than a year after scientists cloned a live sheep named Dolly.
On February 23rd last year, British scientists from the Roslin Institute in Edinburgh said they had created an adult sheep from a single cell taken from the udder of a six-year old ewe. In the experiment to produce Dolly, the nucleus containing all her DNA genetic information was removed from the original donor cell and fused by an electric spark into an unfertilised egg from another ewe. The nucleus, including all the chromosomal material, had been removed from the egg.
The cell, made up of the egg membranes from the second ewe and the nucleus of the donor, developed as an embryo. This embryo contained the identical genetic make-up of the donor.
It was then put into the uterus of a third ewe who acted as the surrogate mother. She was given hormones to prevent her rejecting the embryo. Six months later a lamb was born which is identical to the original donor.
Although the scientific principle behind the process is essentially straightforward, the process within the laboratory is fraught with problems. Dolly was created on the 276th attempt. In all previous attempts the embryo had failed to survive. In a separate experiment, another sheep clone, Polly, was born on July 9th, but this time the experimenters included a human gene in her genetic makeup.
The successful cloning of Dolly and Polly has raised argument over the ethics behind cloning, particularly the cloning of human beings, which experts agree is scientifically possible.
In Britain, Dolly's creators, Dr Harry Griffin, assistant director of the Roslin Institute, and his colleague, Dr Ian Wilmut, while recognising the huge scope and benefits of animal cloning for medical progress, condemn plans to clone human beings as "grossly unethical".
Meanwhile in Chicago, a physicist, Dr Richard Seed, yesterday dismissed President Clinton's denunciation of his plans to clone humans and reaffirmed his determination to do it abroad if necessary.
"I have been enormously encouraged in just one day by calls I have received from infertile couples who are in tears," Dr Seed said on Fox television. "They . . . tell me things like `Don't let them stop you'."
Dr Seed stood firm in his resolve to clone a child within the next two years, saying he would move his enterprise to Mexico if Congress bans human cloning in the US. "My target is to have a two-month pregnancy in a year-and-a-half," he said. "It's not a difficult project."
The Chicago physicist is sure to face difficulty in the US from scientists, ethicists and political leaders who oppose human cloning and say they will work aggressively to block his experiments.
After scientists in Edinburgh cloned Dolly last winter, Mr Clinton sent Congress a bill which would ban, for at least five years, the use of similar procedures to replicate human beings.
Some congressional leaders were saying yesterday, 24 hours after Mr Clinton demanded quick action, they will urgently try to pass the legislation.