Outwardly, there was nothing remarkable about the Finn Dorset ewe that was born at the Roslin Institute in Scotland on 5 July 1996. Yet this little lamb would go on to become the world's most famous sheep, as her very existence sparked a debate which, ten years on, shows no signs of abating. What made this sheep special was the way she was created - for the first time ever, a mammal had been successfully cloned from an adult cell. As the cell in question came from a mammary gland, the lamb was named Dolly, after the famous country and western singer Dolly Parton. Dolly was created through a process called somatic cell nuclear transfer. The nucleus (the part of the cell which contains the DNA) was removed from an egg cell, and replaced with a nucleus extracted from the udder cell of the donor sheep. The resulting cell was then stimulated so that it began dividing. After a few days, the resulting cluster of cells was transplanted into the uterus of the surrogate mother. The announcement of her birth was greeted with a range of reactions. Some were excited at the implications this had for the treatment of degenerative diseases and cancers, while concerns included the fear that the new technology could be exploited to clone dictators. When it heard about Dolly, the European Commission immediately referred the case to its Group of Advisors on the Ethics of Biotechnology. They recommended that while the EU should encourage ethical research on cloning related areas, any attempt to create a human clone by transferring the nucleus of a child or adult's cell to an egg ('reproductive cloning') should be prohibited. They also make the point that even if a human were cloned, the resulting human would not be exactly the same as the original, in the same way that identical twins are different. A number of other animals, including cats, dogs, mice, rabbits and horses, have been cloned successfully since Dolly, and some say that it is only a matter of time before someone clones a human being for reproductive purposes. In 2005, a team of UK researchers successfully cloned human embryos by inserting the DNA from embryonic stem cells into eggs whose own DNA had been removed. However, a human 'Dolly', cloned from a normal adult cell, has yet to be created. For many years South Korean researcher Hwang Woo-suk was a leader in the field of human cloning for therapeutic purposes, and in 2005 he claimed to have created stem cells from human embryos cloned so that they were a perfect match with those of a patient. The claim has since been found to be false, and Dr Hwang is now in court, facing charges of fraud and embezzlement. The revelations have left Dr Hwang's reputation in tatters and South Korea and the international research community in shock. The fact is that cloning mammals from adult cells remains incredibly difficult. Out of 277 attempts by the Roslin researchers to clone a sheep from an adult cell, Dolly was the only lamb born, and success rates have not improved much since then. And while Dolly appeared to be in good health and even gave birth to a number of (naturally conceived) lambs, questions of premature ageing were raised when she developed arthritis at a relatively early age. However, the debate on cloning, and in particular the use of embryonic stem cells, has not gone away, as evidenced during last month's heated debate on the matter in the European Parliament. Those in favour of using EU money to fund research on human and embryonic stem cells won the day, but only by the slimmest of majorities. Italy's recent change of position means that stem cell research should be possible under FP7, subject to national laws and strict controls. Dolly passed away at the age of six, on 14 February 2003. An autopsy confirmed that she had died of ovine pulmonary adenocarcinoma, a lung disease common in sheep. Her remains were stuffed and placed in Edinburgh's Royal Museum.