Scientists claim to have created the first part-human, part-animal hybrid embryos in Europe.
The hybrid embryos -- a blend of human and cow DNA -- which only survived for three days, were developed by a team from the Newscastle University in Britain as part of a basic research on cloning.
According to lead researcher Dr Lyle Armstrong, the hybrids were created by injecting DNA derived from human embryo cells into eggs taken from cows ovaries which have had DNA responsible for their characteristics removed, so called nuclear DNA, and leaving only cow DNA used to power the cells.
Emphasising that the research "is entirely ethical", a Spokesperson for Newcastle University, Prof John Burn, said "there is no intention to put the hybrids into a surrogate mother".
"The purpose of the experiments is to study the way the use of genes alters early in development, so the primary aim of research is basic understanding, not generating stem cells.
"This is licensed work which has been carefully evaluated. This is a process in a dish, and we are dealing with a clump of cells which would never go on to develop. It's a laboratory process and these embryos would never be implanted into anyone.
"We now have preliminary data which looks promising but this is very much work in progress and the next step is to get the embryos to survive to around six days when we can hopefully derive stem cells from them," the British media quoted Prof Burn as saying.
The breakthrough came a month before British Parliamentarians are all set to debate the future of such research in the country.
Dr Evan Harris, the Liberal Democrat MP who led the campaign to ensure that the research was not banned by Parliament, said: "This news is interesting and even exciting but impossible to assess until it has been published and peer reviewed in the usual way.
"That this breakthrough is considered possible in the UK is a further indication of our world leading role in this research and is a demonstration of why it is so important that the Human Fertilisation and Embryology Bill is passed by Parliament -- to maintain that position."