The first patents for cloning have been issued to the researchers who created Dolly the sheep.

The patents cover the so-called nuclear transfer technology itself and any cloned animals produced as a result.

The cloning rights hold for 17 years and give the American owners of the company, Geron Bio-med, which was licensed by Dolly's creators to exploit the new science, sole rights to a technology that could help doctors grow living tissue for use in human transplants.

Critics argue this gives one commercial organisation too much control over something that promises to revolutionise medicine in the 21 Century. It could even act to slow down the development of new therapies, they say.

But these fears were rejected by Simon Best, managing director of Geron Bio-med.

"History has demonstrated amply over the last hundred years that the establishment of one patented technology is the biggest spur to innovation through other technologies," he told the BBC.

Cell therapies

Dolly was brought into the world in 1996 by a research team led by Drs Keith Campbell and Ian Wilmut at the Roslin Institute, just outside Edinburgh, Scotland.

 Ian Wilmut describes how his team created Dolly

Although much controversy at the time centred on the possible use of the Dolly technique to create human clones, the scientists always insisted that nuclear transfer would only be used to develop new cell therapies.

To pursue this work, they set up Roslin Bio-med, which was subsequently bought out by the Geron Corporation from California last year.

Geron brought to the newly-named Geron Bio-med company their expertise in stem cells, the master cells in the body that can become any type of tissue - bone, muscle, nerve, etc.

This expertise, combined with nuclear transfer, could allow scientists to "reprogram" cells and grow tissue for transplants that would not be rejected by a patient's body.

Now, because of the issuance of the patents, anyone who wants to attempt this type of work would be liable to pay a fee to Geron.

Custic fibrosis

The patents currently operate in the UK only, although US patents are also likely to be issued in the next few months.

There is an exclusion that covers the work done by another offshoot of the Roslin Institute called PPL Therapeutics. It has exclusive rights to the technology to clone animals that express human proteins in their milk.

This type of "pharming" is already being used to make drugs for treating diseases like cystic fibrosis.

Shares in Geron Biomed jumped sharply upwards when news of the patents was announced.

The patents, numbered GB 2318578 and GB 2331751, and are jointly owned by the Roslin Institute, the UK's Biotechnology and Biological Sciences Research Council (BBSRC) and the government through its Ministry of Agriculture, Fisheries and Food (MAFF).

The patents and the various commercial tie-ups agreed by Roslin will see substantial amounts of cash flow into the publicly-funded Scottish research centre.

The Church of Scotland called on the scientists not to abuse the patents.

Dr Donald Bruce, of the church's Society, Religion and Technology Project, said: "Society has given Geron and their collaborators certain rights. In return we must now require Geron to exercise a clear social responsibility on how they use those rights.

"They must ensure that the benefits of their research are available not just to a few rich patients but to all. This means putting human needs before profits. They must ensure that their position will only be for ethical purposes."