the embryo, which is a collection of cells that could develop into a fully formed human, is destroyed, even though embryos in these procedures are left over from in vitro fertilization.
However, Mitalipov said the embryos created in his study, from skin cells and eggs, would not grow babies. That would have required additional technology, and it wasn't part of the study.
While cloning stem cells is a technical breakthrough, there's already a method of deriving embryonic-like stem cells that doesn't require the use of embryos at all: induced pluripotent stem (IPS) cells, said Dr. George Daley, who is director of the Stem Cell Transplantation Program at Children's Hospital Boston and an international expert in stem cells.
Induced pluripotent stem cells can come from any cell in the human body, including skin cells, so they don't have the moral quandaries surrounding them. Researchers have developed methods of inserting genes to "turn back the clock" on cells that have already specialized, so that they can turn into anything again. It doesn't matter what the cell was before; it can now be reprogrammed as any kind of cell researchers want.
The new study involves a complex method that requires women to donate eggs, and a demanding manipulation of cell components on a tiny scale, Daley said.
What remains to be seen is whether these cloned embryonic stem cells are more useful therapeutically than the noncontroversial induced pluripotent stem cells, and questions linger about their effectiveness.
What's the best type of stem cell
Ethical questions aside, researchers say they need to explore both embryonic and induced pluripotent stem cells in order to see what works best for various diseases and conditions.
Safety concerns linger around induced pluripotent stem cells because they were first created inserting four new genes.