The first animal to human transplants in Britain could begin within months following a UK government decision last week to create formal regulations for the technology, known as xenotransplantation. The British Minister for Health, Mr Frank Dobson, established a working group to study disease transfer risks and the creation of the UK Xenotransplantation Interim Regulatory Authority which will oversee requests to apply the techniques. One Cambridge-based company, Imutran, is understood to be ready to apply for permission to use genetically altered pig livers to help keep liver transplant patients alive until a permanent human donor could be found. The company has already used this technology to transplant pig hearts into monkeys in 1995. Xenotransplantation throws up many health and ethical hurdles, however. There are fears that animal viruses or infections could "jump" to human transplant recipients, creating a new category of disease. Animal rights groups also question the ethics of developing animals bred for transplantation purposes.