High-interest clones

When, in 2004, Woo Suk Hwang claimed to have produced a stem-cell line derived from an embryonic human clone, his research, done at Seoul University, sparked intense interest and hype. Even though Hwang's work later proved to be fraudulent, all advances in the field risk being measured against it. At the same time, researchers seek to distance themselves from the episode to the extent that its ethical implications for current work are rarely discussed.

This week, scientists have come the closest of any so far in emulating Hwang's claimed results: on page 70, researchers from the New York Stem Cell Foundation Laboratory report using cloning technology to reprogram human DNA taken from an adult and create embryonic stem cells. But they do not use the term cloning to describe their results. That is one of many contrasts between the research landscape now and in 2004.

Hwang's claims received worldwide attention. Patient groups jumped for joy; scientists around the world used the results to gather more funds for stem-cell research; and bioethicists emerged to justify or condemn the work. Reaction...