Why does God kill so many babies before they are born?

I’ve often wondered how religious conservatives, who believe that a fertilized egg is a human being with a soul, react to the central fact of Ronald Bailey’s aptly entitled piece, Is Heaven Populated Chiefly by the Souls of Embryos?

What are we to think about the fact that Nature (and for believers, Nature's God) profligately creates and destroys human embryos? John Opitz, a professor of pediatrics, human genetics, and obstetrics and gynecology at the University of Utah, testified before the President's Council on Bioethics that between 60 and 80 percent of all naturally conceived embryos are simply flushed out in women's normal menstrual flows unnoticed. This is not miscarriage we're talking about. The women and their husbands or partners never even know that conception has taken place; the embryos disappear from their wombs in their menstrual flows. In fact, according to Opitz, embryologists estimate that the rate of natural loss for embryos that have developed for seven days or more is 60 percent. The total rate of natural loss of human embryos increases to at least 80 percent if one counts from the moment of conception. About half of the embryos lost are abnormal, but half are not, and had they implanted they would probably have developed into healthy babies.