“As the FDA recently delayed approval of a private sector proposal for Phase I clinical trials of an embryonic stem cell therapy, the need to evaluate U.S. policies on clinical application of embryonic stem cells seems especially pertinent.”

Indeed, the United States is on track for the first clinical trials. And I would agree and also add emphasis to your sentiments about exercising caution in approving the trials. Although the FDA has not yet indicated why it delayed the trials, I am willing to guess that it has to do with safety concerns. This is why I believe that evaluating policies on clinical application is especially pertinent. This means not only ensuring FDA regulation, but also ensuring that the studies receive IRB approval and oversight and also giving attention to the NAS and ISSCR guidelines for embryonic stem cell research and clinical translation. As in the case that you highlighted, even with all of these oversight mechanisms we can still have serious and tragic outcomes, so we need to be especially careful as this field is pioneered.

“Aside from highlighting the lack of therapies in the United States, this situation underscores a need to promote scientific progress in the U.S. through federal funding of embryonic stem cell research. As the FDA recently delayed approval of a private sector proposal for Phase I clinical trials of an embryonic stem cell therapy, the need to evaluate U.S. policies on clinical application of embryonic stem cells seems especially pertinent.”

implies that the U.S. is an outlier with respect to embryonic stem cell therapies and clinical trials. Just to be clear, there are neither valid embryonic stem cell therapies nor embryonic stem cell clinical trials anywhere in the world. Regarding the latter, the US is on track to host the first clinical trials. But given the high stakes, political polarization, and enormous attention given to such potential trials, everyone benefits if these proceed cautiously, not hastily. One merely needs to look at the case of medical gene transfer for a hyped, novel field that was greatly set back when a tragedy occurred, largely due to haste and lack of oversight.