Stem cell research could provide one of the big medical break-throughs of the next few years.

Scientists claim it could lead to treatments for such debilitating diseases as Alzheimer's, Parkinson's and diabetes.

The problem is that the research seems to require the use of human embryos - which is hotly opposed by many, especially members of the Roman Catholic Church.

However Catholic researchers hope they may have found a way round the difficulty - and today the Catholic University of Rome is setting up what is called a placenta bank - which it is hoped will provide a more ethically acceptable source of stem cells.

Stored cells

Doctor Michael Jarmulowicz of the Guild of Catholic Doctors says the bank will store blood cells from placentas and umbilical cords for use in the research.

He says this is an ethically acceptable way of producing the material and it should be as scientifically useful as cells derived from embryos.

Limited use

However, not everyone in scientific world agrees. Professor Steve Jones of University College London says the "placenta bank" is of limited use.

He says stem cells from placentas are only blood cells and are already used to treat some blood disorders with some limited success.

Cells from embryos, he says, hold more potential to become other tissues and thereby be developed to tackle other complaints.