The point that I want to make is that a lot of the enthusiasm and emotion that has driven human embryonic stem cells is the idea that we'll use this for transplantation and cure diseases like Parkinson, and while I think in limited cases that might be true, I think broadly it will prove extraordinarily challenging. And if you look at the field say 10 to 20 years from now, there'll be some stellar successes in the transplantation realm, but there'll be a lot of failures, and I think people are ill-prepared for the risks of a new technology like this.
http://plosgenetics.org/article/info:doi/10.1371/journal.pgen.1000182#article1.body1.sec1.p95

he is actually doubt about future therapeutic potential?