Stem Cell Revival: The 1990s are Back

"SINCE what works in sheep is likely to be possible in humans, we are suddenly propelled right past the imagined techniques of Brave New World." That was how New Scientist greeted the news, in March 1997, of the creation of Dolly the cloned sheep.

It has taken longer than expected. More than 17 years later, what worked in sheep finally appears to be working in humans (see "Insulin-making cells created by Dolly-cloning method"). This is a potentially major medical breakthrough, but no longer feels as challenging as it once did. In fact, after endless hope, hype and failure, it is hard to feel there is anything brave or new in this line of research.

To say stem cell science has a chequered past would be an understatement. Those with long memories will recall that South Korea's fallen stem-cell hero Woo Suk Hwang falsely claimed to have replicated the Dolly technique in humans in 2005.

Controversy has dogged the field ever since. Because the Dolly technique involves the destruction of human embryos, its ethical dimensions have been...