For cosmetic surgeons, it would represent the ultimate operation - a victory over the ageing process that would consign face-lifts, Botox injections and anti-wrinkle creams to history. Instead of repairing old, saggy faces, why not replace them with fresh, young, taut ones? The idea has the nightmare quality of science fiction. But in this case science fiction is becoming science fact - and surgeons could make a start tomorrow.
Some are already itching to give it a go. Teams in the US, Britain, France and Columbia are researching the technique of face transplantation and it is only a matter of time before someone attempts it. All that is restraining them is their research ethics committees and their own consciences. The first candidates for such radical surgery would be people disfigured by accident or disease. But the Royal College of Surgeons last week looked further ahead to the time when the treatment may have become established - even routine.
"Once a treatment exists," it said, "increasing numbers of people try to track it down. In the case of facial transplantation the example of the ageing rich seeking to look more youthful has been cited."
The college has gazed into its crystal ball - and seen a future peopled with Dorian Grays. But there is a long way to go before it comes to pass and the college tried to slow its arrival last week by publishing a report calling for a moratorium on the surgery until more research has been done.
It had been alarmed by the hype around the operation triggered a year ago when a British surgeon, Peter Butler, of the Royal Free Hospital, announced that face transplants were technically possible - easier than stitching back a finger, it was claimed last week - and he and his team were investigating them. Ten people contacted Mr Butler for more information, prompting a frantic scramble by the tabloid press to identify the first likely candidate for the groundbreaking surgery.
The royal college decided the best way to curb the stampede and inject some balance into the debate was to set up a working party to examine the issues. The launch of its report last week was a surprisingly gloomy affair, given the excitement that the operation has generated in plastic surgery circles. Sir Peter Morris, the president, insisted they were not averse to the idea of face transplants, merely cautious about the risks. But the overwhelming view of the group was that this was not an operation that could be justified in the light of current medical knowledge, nor likely to become so in the near future.
Most transplants of whole organs are life saving, so risks are acceptable because the alternative is death. But face transplants are about improving the quality, not the quantity of life and failure could be devastating. One horrendous scenario spelt out by the group was of a person who has a transplant of the skin, underlying tissue and muscle of the face. Should that fail and have to be removed, the recipient would be left, potentially, with nothing but a skull and a few muscles for chewing - literally, faceless.
The main barrier to success is rejection. Even assuming the transplant went well and the recipient became used to their new face, there would be the nagging worry that it might go wrong. The skin provokes the strongest immunological reaction when transplanted and it is estimated that in up to half of cases, thickening of the tissues and unsightly scarring could develop in two to three years. The key would be to induce "transplant tolerance" - a state in which the immunological reaction is overcome without the need for anti-rejection drugs. This is the Holy Grail of transplantation. Sir Peter Morris, the president of the Royal College of Surgeons, said last week he had spent his entire professional life working on it and while he wished for a breakthrough it was "not around the corner."
Despite these caveats, it is virtually certain that someone, somewhere will proceed with a face transplant in the not too distant future. The history of transplantation is of maverick surgeons challenging the prevailing orthodoxy until their radical procedures become mainstream. When Christiaan Barnard carried out the first heart transplant in 1967 in South Africa there were protests that he was interfering with men's souls. When the first hand transplant was carried out in 1998 there were warnings that the recipients would experience major psychological and rejection problems - and some have done so. But 20 hand transplants have been carried out to date and the operation is becoming a rare, but viable, option.
In face transplantation, these problems would be magnified. The face is central to our understanding of our own identity and disruption to it causes a profound disruption of our body image, as the college says. But if the rejection problems could be overcome, the gains for people disfigured by accident or disease could be very great. We should not let our revulsion at the idea of swapping faces deter those trying to make it happen.