By Emma Wilkinson
BBC News, health reporter
Traditionally organ transplants have been carried out to save a person's life, be it with a new heart, kidney, or set of lungs.
Surgeons are starting to carry out womb, face and hand transplants
But surgeons are increasingly looking at transplants as a way of improving a patient's quality of life.
Womb, face and hand transplants have all hit the headlines in recent months and these elective procedures raise difficult ethical questions.
For example, what happens if the donor organ is rejected.
Neil Hubard, a spokesperson for the Face Trust, said in the case of womb and face transplants, donor selection was much more stringent than with life-saving transplants such as heart or kidneys.
"The criteria for selection is crucial. We have to get the right person. Then we look at very very fine tissue matching."
Patients must also be assessed for their psychological suitability.
"The people who want this kind of transplant are in a hell of a psychological state," he said.
"And one of the reasons selection is absolutely crucial is we have to advise people that taking immunosuppressants over long periods of time can be life-threatening and life-shortening."
In the case of womb transplants, surgeons are only planning to keep the donor organ in place for one or two pregnancies before removing it again.
Doctors are also looking into new ways of avoiding rejection in face transplants, for example with the use of creams.
He said that painstaking research on face transplants had been going on for the past 14 years and there had been eight to nine years of womb transplant research in the UK.
"The key thing is that we and other teams believe in taking a very long and cautious route and we're not going to rush it."
Dr Richard Nicholson, editor of the Bulletin of Medical Ethics pointed out that non-vital transplants were not necessarily a new phenomenon as the first even transplants to be done were of the cornea.
However, he expressed serious concern about the new forms of transplant that science was beginning to make available.
Dr Nicholson warned that patients may not fully appreciate the implications of agreeing to a transplant - and have unrealistic expectations.
"People could have grave psychological problems," he said.
"They can be informed about the risks, but people who are willing to undertake something like a face transplant are probably not of an open mind.
"We know that people have unrealistic expectations of medical research and believe they are bound to do better than if they didn't have the procedure."
He also warned that the possibility of rejection was not only potentially damaging psychologically - it could make a bad situation worse physically too.
"When something is rejected it becomes a great deal more difficult to replace it with another organ.
Mr Robert Johnson, past president of the British Transplantation Society said it was inevitable that surgeons would try to find new applications for procedures such as transplantation once they had been shown to work.
"The thing to bear in mind is that transplantation is a very dangerous exercise because you break down the body's defence mechanisms and that is absolutely justifiable when you are doing something life-saving.
"I can understand that people are prepared to take the risk with face transplants as they are almost prepared to do anything and there is justification for hand transplants providing it is right down at the wrist.
"But with wombs I think you're very close to the dividing line."