In an advance that could solve many of the ethical and technical issues involved in stem cell research, two groups of scientists have independently converted human skin cells directly into stem cells without creating or destroying embryos.
"We are now in a position to be able to generate patient- and disease-specific stem cells without using human eggs or embryos," Shinya Yamanaka, leader of one of the research teams at Kyoto University in Japan, said in an e-mail interview.
Preliminary tests show that the newly created cells can develop into nerve cells, heart cells, or any other kind of cell in the body. Previously, only stem cells taken from early embryos had this kind of flexibility, called pluripotency. Scientists have suggested that such embryonic stem cells could be used for learning about genetic diseases, testing new drugs on cells grown in the lab, or growing healthy cells for therapeutic transplantation.
Producing embryonic stem cells has become controv