In the 1990s, gene therapy was the Next Big Thing in biotechnology. It was touted for a huge array of ailments -- but it came to a screaming halt in 1999 with the death of 18-year-old Jesse Gelsinger in a clinical trial. This even changed the life of the scientist in charge of that failed experiment, James M. Wilson of the University of Pennsylvania.

Now Wilson has published an essay in Science arguing that stem cell science is on the same track to disaster: “In today's clamor of stem cell enthusiasm it is possible to detect haunting echoes of the early and ultimately troubled days of gene therapy.”

The same forces which made him imprudent then exist today, says Wilson.

“Many of the factors that fueled gene therapy's premature expansion are major drivers of the hESC and iPS research agenda today. A large and vocal population of patients suffering from a wide variety of ailments is pressing for stem cell–based therapies. Disease-specific stem cell research groups are more politically sophisticated than ever, in some cases employing congressional lobbyists. Unrealistic expectations have been fueled by relentless media coverage, driven in part by a factor not present in the gene therapy roll-out: a debate over the ethics of research on human embryos and embryo cells, which has served as a "news hook" that brings media attention to even the most incremental of advances.”

He sees the amber light flashing in Geron’s clinical trial of embryonic stem cells for curing recent spinal cord injuries. News coverage was remarkable for its lack of restraint, he says, with the media describing federal permission to test the cells in patients as a "breakthrough"

In a separate interview in Nature, Wilson says that he has some serious concerns about stem cell research in the United States. In the first place, it is not transparent enough. There is no mechanism for public disclosure of what is being approved and conducted and there is no requirement for public disclosure of adverse events.

A number of other critics of embryonic stem cell research have pointed out that it could be dangerous, but it comes with more conviction from Wilson.

“Many of the issues that have caused problems in the clinic for gene therapy are relevant to stem cells. One is delivery of the cells. Another is immunogenicity — if you're using cells donated from another individual, they'll be viewed as foreign and cause very complicated immune responses. The third is that embryonic stem cells may transform into tumour cells, and there's already some evidence of that from one study. The field needs to pay attention to those areas.” ~ Science, May 8; Nature, May 7