I'm often amazed by claims that stem-cell research is somehow brutal to the embryos that are destroyed as part of the process, as though this were analogous to clubbing a child to death.
Let me draw on a few thoughts in my Journal of Medical Ethics article, "Stem-cell research on other worlds", and see if I can make the point once and for all. (Of course, I can't: the point needs to be made over and over, like every worthwhile point.)
Think about the early embryo, marked for destruction. First of all, there is no rational justification for thinking of it in the emotionally-charged and culturally rich ways that we inevitably think of babies and young children. We can be glad that we think of babies in that way - it conduces to family happiness, to the education and socialisation of growing human beings, and ultimately to social survival. But we don't have to extend that kind of thinking down to the most nascent human life.
Unlike children and adults, the embryo does not fear death. It cannot look forward to its birthday, or Christmas, or a hot date with the sexy redhead or dark-haired hunk who sits in the back of the science class. It is incapable of planning books or curricula or golf tournaments, of identifying with political causes, having a beer with a few mates, or falling in love. It has no networks of kin, loved ones, dependents, colleagues, or fans of the same football team, and it cannot commit itself to any projects that give it reasons to want to go on living and developing. Indeed, it has no wants. There is nothing at all that it is like to be an early embryo, and if death is a misfortune for it in some way, it is certainly not in the same way as for a human child, teenager, or adult.
Early embryos can't be treated brutally or harshly. They have no meaningful interests. If there is some kind of misfortune for an early embryo in never developing to point of being born, it is difficult to see why any moral weight should be put on a need to avert that kind of strange, abstract misfortune. Surely any so-called "interest" that we attribute to an entity which is unable to suffer pain or frustration, has no forward-looking subjective attachments to life, and does not know fear cannot outweigh the interests of actual adults and children whose lives, well-being, and hopes for the future depend on the development of new, effective medical therapies.
That won't be the end of the debate, but it really ought to be. I see nothing more that needs to be said.