Scientists have used a cloning technique to create patient-specific embryonic stem cells to grow in unfertilised human egg cells for the first time.

The researchers, from the New York Stem Cell Foundation, used a cloning technology called somatic cell nuclear transfer (SCNT) to make embryonic stem cells that match patients' DNA.

The test, reported in the journal Nature, is a significant development in stem cell research and the authors say the results could impact the study and treatment of diseases such as diabetes, Parkinson's and Alzheimer's.

Patient-specific cells can potentially be transplanted to replace damaged or diseased cells in patients without rejection by their immune system. However, the scientists said that more work needs to be done before cells can be used in cell-replacement medicine.

Stem cells are "mother cells" capable of transforming into a range of different tissues.

Those extracted from early stage embryos have the potential to become virtually any kind of tissue, from brain to bone. Others, partially developed adult stem cells, have a more restricted set of development pathways.

The standard cloning technique involves removing the nucleus from an egg and the core is then replaced with the nucleus of a cell from the donor and then nurtured in laboratories, the method used with Dolly the sheep in 1996 - the world's first successfully cloned mammal.

However, lead researcher Dieter Egli and colleagues left the egg's DNA intact and added DNA from an adult donor cell. But the cells which were developed have an abnormal number of chromosomes so they are not yet ready for therapeutic use, the researchers added.

"This paper will be seen as significant both by those who are trying to use SCNT to produce human patient-specific embryonic stem cell lines and by those who oppose human 'cloning' experiments," said Professor Robin Lovell-Badge, a division head at Britain's National Institute for Medical Research.

Chief executive officer of the New York City-based foundation, Susan Solomon, said: "The ultimate goal of this study is to save and enhance lives by finding better treatments and eventually cures for diabetes, Alzheimer's, Parkinson's and other debilitating diseases and injuries affecting millions of people across the US and the globe."