Basically, the letter makes the false claim that proponents of a prohibition on human cloning would have somehow prevented the recent "direct reprogramming" breakthrough from becoming reality.
What hogwash. First, legislation in Missouri was always aimed at outlawing human cloning, not embryonic stem cell research. Indeed, ESCR would have remained perfectly legal in MO if A. 2 had failed. Second, the potential repeal pending in MO would really outlaw human cloning, and not impede ESCR in the least. Third, cloning had zero to do with the iPSC breakthrough, and indeed the new approach is seen widely as a moral and ethical way to derive pluripotent stem cells without SCNT cloning. Fourth, Bush-approved ES cell lines were and are perfectly suitable for the kind of basic research into pluripotency that scientists say they need to continue to perfect iPSCs. Finally, James Thomson, one of the scientists who demonstrated the viability of the approach, did so with an NIH grant from the dreaded Bush Administration.