Saturday, 28 December, 2002, 11:13 GMT

One of the most controversial issues in medical science in 2002 was the development of stem cell technologies.

The debate looks set to continue in 2003, with researchers keen to start full clinical trials.

The field of biological research has been heralded as the development that will provide cures for diseases such as Parkinson's and Alzheimer's.

It could eventually allow doctors to grow organs and tissues for transplants.

None of these dramatic promises have yet been achieved, however, despite the hype.

Recent announcements suggest that more clinical trials could start in the New Year.

However, just as the pace of research seems to be speeding up, the problems that scientists need to overcome are also mounting.

Repairing damage

Stem cells could potentially change the way diseases are treated. Scientists hope they will one day be used to replace cells which have died or stopped working, in diseases like Alzheimer's, multiple sclerosis and diabetes.

Until recently it was thought that the most versatile and useful types of stem cells came from embryos or foetuses, as these can develop into any kind of cell in the body. But their use presents a minefield of ethical dilemmas.

Human embryonic stem cells are taken from embryos that are just a few days old, destroying the embryo, while foetal stem cells are taken from aborted foetuses.

In many countries the debate about what type of research should be allowed and what should not rages on.

Remainder

-- Anonymous, December 28, 2002