She was the world's most famous sheep whose birth 20 years ago brought hope for curing illnesses and fears over the future cloning of humans.

Dolly the Sheep, who was born on July 5 1996, is still the subject of scientific and ethical debate two decades on as a series of events have been lined up to mark the anniversary.

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Professor Sir Ian Wilmut, the scientist who led the team at the Roslin Institute, near Edinburgh, which cloned Dolly from an adult cell sending shockwaves around the world, is among those involved in events over the summer.

The celebration programme includes Coming of Age: The Legacy of Dolly at 20, a public lecture and discussion at the Surgeon's Hall in September and open days at the Roslin Institute, Easter Bush Campus

In another event Professor Helen Sang of the Roslin Institute, Dr Tilo Kunath, MRC Centre for Regenerative Medicine, and Dr Miguel Garcia Sancho Sanchez, School of Social and Political Science, to debate whether Dolly has a place in the 21st century or if she should be consigned to the history books.

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The project was said to be "only ever a small part of a much bigger research programme and the cloning technique used to produce her has now been overtaken by newer, better technologies".

The Roslin Institute, which is examining her legacy, said: "Dolly was important because she was the first mammal to be cloned from an adult cell.

"Her birth proved that specialised cells could be used to create an exact copy of the animal they came from.

"This knowledge changed what scientists thought was possible and opened up a lot of possibilities in biology and medicine, including the development of personalised stem cells known as iPS cells."

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Ten years ago Professor Wilmut courted controversy when he said despite being implacably opposed to cloning human beings that the process could be used to help people.

In a book he released at the called After Dolly he said it would be immoral not to use the promise of new technology to help families, arguing that when the techniques are safe, society should consider cloning with genetic modification to prevent the birth of babies with serious diseases.

Church leaders criticised his comments as he described the potential of taking an embryo affected by a hereditary disease and then removing its stem cells and modifying the genetic fault which, left unchecked, would cause a condition such as Huntingdon's disease or cystic fibrosis.

He also said in the book which he co-wrote with English journalist Roger Highfield: "An early embryo is not a person, and I see the use of cloning to prevent a child having a dreadful hereditary disease as far less controversial."

When Dolly was one year old there were signs she could have been "older" than her actual age but extensive health screens on Dolly at the time did not find any conditions which could be directly related to premature or accelerated ageing.

When being tested in 2003 a CT scan showed tumours growing in her lungs and the decision was made to euthanise Dolly, who had a total of six lambs with a Welsh Mountain ram called David, to prevent her suffering

The taxidermied and mounted Dolly took centre stage at an exhibition last year after being gifted by the Roslin Institute to the National Museum of Scotland and a plaque celebrating Dolly and the team who created her, which was made up of many different people, including scientists, embryologists, surgeons, vets and farm staff, was unveiled by the Society of Biology at the Roslin Institute, Edinburgh University.