NEW YORK — Scientists have made ordinary human skin cells take on the chameleon-like powers of embryonic stem cells, a startling breakthrough that might someday deliver the medical payoffs of embryo cloning without the controversy. Laboratory teams on two continents report success in a pair of landmark papers released Tuesday. It’s a neck-and-neck finish to a race that made headlines five months ago, when scientists announced that the feat had been accomplished in mice. The ‘direct reprogramming’ technique avoids the swarm of ethical, political and practical obstacles that have stymied attempts to produce human stem cells by cloning embryos. Scientists familiar with the work said scientific questions remain and that it’s still important to pursue the cloning strategy, but that the new work is a major coup. ‘This work represents a tremendous scientific milestone-the biological equivalent of the Wright Brothers’ first airplane,’ said Dr. Robert Lanza, chief science officer of Advanced Cell Technology, which has been trying to extract stem cells from cloned human embryos. ‘It’s a bit like learning how to turn lead into gold,’ said Lanza, while cautioning that the work is far from providing medical payoffs. ‘It’s a huge deal,’ agreed […]