A revolutionary technique using stem-cell research could soon allow women to choose breast enhancements made of living tissue instead of silicone.
Scientists have been able to grow human fat cells in the laboratory for the first time. They say the breakthrough means patients could, in effect, grow their own implants.
The researchers also claim that, in the longer term, it may be possible to grow replacement organs for transplant surgery.
The target patients are cancer sufferers and others who need reconstructive surgery. But the man pioneering the technique, Jeremy Mao, professor of tissue engineering at the University of Illinois in Chicago, acknowledges there could also be a substantial cosmetic market.
Doubts persist about silicone or saline implants which, despite technical improvements, can rupture or leak.
About 15,000 women had cosmetic surgery in Britain last year, up from 9916 in 2003, according to the British Association of Aesthetic and Plastic Surgeons.
In the United States, about 6.2 million people annually need plastic surgery for medical reasons, mostly following the removal of a tumour. The same number have plastic surgery for cosmetic reasons.
Professor Mao has developed a method of isolating the patient's stem cells, culturing them into a fatty tissue mass, and then building it round a "scaffold" of the correct shape for breasts or lips.
He said he first took adipose stem cells from a human donor and isolated the fat-generating cells. These were mixed with a chemical, hydrogel, "which can be moulded into any given shape or dimension". Hydrogel is a lightweight material licensed for use in medicine.
"You mould them into the shape of the other normal breast or the missing portion of breast and, instead of implanting silicone or saline structures, we would use the stem cell-derived adipose implant," Professor Mao said.
The living tissue implants would not "wear out". And because they are derived from the patient's own stem cells, there would be no problem of tissue rejection, which can arise with tissue from a donor.
"The technique is also applicable for other soft tissue, including facial tissue such as the lips," he said.
"Patients will have a choice - a stem cell-grown structure or an artificial implant."
But a number of issues are yet to be resolved. One is the question of how the mass of living cells can develop a blood supply to keep it alive once it is implanted.
Another is how to stop the cells from continuing to replicate once the operation is complete.
In the long term, scientists hope that it will be possible to culture stem cells into complete organs, or parts of organs. This would allow transplants to take place without rejection by the patient's body.
More than 100,000 British women are estimated to have had implant surgery, although exact figures are difficult to pin down. Health fears circulated after a US study found that up to 70 per cent of silicone implants ruptured.
Many women switched to versions using soya oil - discontinued in Britain in 1999 over leak worries - and saline.
In 1998 in Britain, a Government review found no evidence that silicone presented any greater risk than other implants.
There is growing unease in the medical profession at the level of interest in plastic surgery, which has been partly fuelled by TV programmes such as Nip/Tuck.
The British Association of Plastic Surgeons has said that the public obsession is leading to inappropriate referrals and encouraging poorly qualified surgeons to become involved.
200 years of implants
* Materials such as ivory and sponge were inserted into women's breasts to enhance shape and size in the 19th century.
* By the 1940s breasts were being directly injected with paraffin and silicone derivatives.
* Silicone gel implants were introduced in the early 1960s. Soya oil and saline versions have also been used.