No "rational" reasons to oppose stem-cell research?

In this story, from today's New York Times, about a method of extracting cells for research purposes from embryos without destroying those embryos, quotes Dr. Robert Lanza, vice president of Advanced Cell Technology, as saying that "[t]here is no rational reason left to oppose this research."

For starters, I wonder if Dr. Lanza means to suggest that he thought there were "rational" reasons for opposing embryonic stem-cell research before?

Putting that aside, I find this statement baffling.  Perhaps Dr. Lanza just means, "look, the arguments against stem-cell research were really weak before, when they centered on causing the death of embryos, but now -- given that we are throwing the Luddites a bone and trying to avoid killing the embryos -- the objectors really should be mollified."  Here, however, is a link to a White Paper produced in 2005 by the President's Council on Bioethics which identifies a number of concerns which would seem to supply, at the very least, "rational" reasons for being concerned about the research described in the Times article.  For example, if it is "rational" to worry about research that intentionally causes the death of human embryos, perhaps it is also "rational" to worry about research that seems likely to involve the reckess causing of embryos' deaths?