Stem Cell Breakthrough Could Stifle Research

Last week independent teams of scientists announced a major advance in stem cell research with their discovery of how to turn human skin cells into an "embryonic" state, enabling these cells to grow into nerve, heart or other types of human cells.

The method does not require the destruction of discarded human embryos from fertility clinics, currently the only source of embryonic stem cells. Thus, this would bypass the ethical concern that prompted the Bush White House to sharply limit funding on stem cell research.

Great news, maybe. Never has such a breakthrough been so worrisome to scientists. The discovery, albeit promising, might stifle stem cell research or send it down a dead-end path, for it is now harder than ever to secure funding to study the best source of embryonic stem cells-that is, embryos.

Turning back the clock

Embryonic stem cells come from an early-stage embryos called blastocytes. A blastocyte is a hollow ball of about 50 to 150 cells that forms a few days after fertilization in humans. These cells are pluripotent, meaning they can develop into...