Teams of Chinese scientists managed to produce 27 live mice from stem cells taken from the skin tissue of adult mice and then reprogrammed, according to the journal Nature.

A leading stem cell researcher said the work is important because it shows that the new type of stem cells "satisfy the most stringent criteria of embryonic stem cells."

"We are confident that tremendous good can come from demonstrating the versatility of reprogrammed cells in mice," Fanyi Zeng, associate director of the Shanghai Institute of Medical Genetics, wrote in an e-mail to The Associated Press.

Some scientists expressed caution in the study because the stem cells were only tested on mice and have not yet lead to useful results in humans.

Dr. George Daley, who does research at the Children's Hospital and Dana-Farber Cancer Institute in Boston, expressed his caution.

"This very exciting paper proves that some iPS cells can perform like embryonic stem cells in making a whole mouse from cells in a petri dish," he said. "This does not prove that all iPS cells can do this."

Source: ABC News