Scientists have become rather free in their attempts to do something novel with embryonic stem cells. I am linking an article here from Dr. Jones (not the movie guy; in fact, not a guy at all), where she argues for prudence in the practice of parthenogenesis. The article is a bit technical, but it is helpful since she makes the argument that trying to define humanity along the lines of “viability” is dangerous. If there is a point at which a human entity is considered “not a human being,” then, at that point, we might still be able to destroy it or experiment with it for purposes we think are good. She points out in this article that taking such an approach would lead to more killings of babies considered genetically imperfect. Why not experiment on the sick and elderly once they are no longer viable on their own?
One of the fascinating realities of our post-abortion mindset is that we will defend the protection of an eaglet (not a viable entity on its own) but refuse even to acknowledge the human nature of a human being in development. I have linked a story here to give you an idea of just how highly we value eaglets (non-viable on their own) and eagles’ nests. If only we valued developing humans and the womb as much! For a philosophical consideration of the issue of viability, see this article.