One of the marvels of modern medicine is the organ transplant. Many people who would have died simply because their blood-pump stopped working properly are now alive and thriving because of heart transplants.

But there is a severe shortage of organs and many die before a suitable one becomes available.

This is where pigs may help.

The news that viruses found in pig tissue do not appear to infect humans should be welcomed because it overcomes one of the major practical barriers to using pig organs in humans.

Ethical debate

Most people have no objection to using pigs - they are used for food already. We also use many tissues from pigs including heart valves and skin grafts already, so using an entire organ such as the heart to save a life should not raise any new ethical debate.

Pig organs may only be the medium term solution

Pigs are favoured by scientists because they have many similarities to humans. Their hearts are about the same size as ours with similar plumbing and power output. What is more, they would require only a minor bit of genetic engineering to be compatible with our immune systems.

The scientists at the Roslin Institute who created Dolly are using this expertise to develop pig clones suitable for transplants. So expect the first pig hearts to be transplanted into humans in just a few years.

But it may be a short-lived phase. The days when we crudely transplant a heart from a human or a pig may be numbered. The real breakthrough may come from cloning and tissue engineering research.

Perfect-match tissue

Why bother with adapting the cells and organs of other species when there is the possibility of manipulating human cells to do the same thing far more efficiently.

If you are unfortunate to have a diseased heart, what could be better than growing a new one out of your own cells? There would be no compatibility problems and surely no ethical ones.

This may be possible, or rather, will be possible in perhaps a decade. Across the world, many scientists are working to achieve this goal. A team from the University of Toronto has said it wants to create a tissue-engineered heart suitable for transplant within 10 years.

And a team of scientists from Boston, US, are developing a technique where you could grow a new organ actually inside your own body.