More on the "murder" of embryos

Quoted from A Companion to Genetics, Eds. John Harris and Justine Burley (Blackwell Publishing, 2002), by Richard Dawkins in his article Collateral Damage Part I in the Dec 2006/Jan 2007 Free Inquiry magazine:

We now know that for every successful pregnancy which results in a live birth, many, perhaps as many as five, early embryos will be lost or miscarry (although these are not perhaps "miscarriages" as the term is normally used, because this sort of very early embryo loss is almost always entirely unnoticed). Many of these embryos will be lost because of genetic abnormalities, but some would have been viable. How are we to think of the decision to have a child in the light of these facts? One obvious and inescapable conclusion is that God and/or nature has ordained that "spare" embryos be produced for almost every pregnancy and that most of these will have to die in order that a sibling embryo can come to birth. Thus the sacrifice of embryos seems to be an inescapable and inevitable part of the process of procreation. It may not be intentional sacrifice, and it may not attend every pregnancy, but the loss of many embryos is the inevitable consequence of the vast majority of (and perhaps all) pregnancies. For everyone who knows the facts, it is conscious, knowing, and therefore deliberate sacrifice; and for everyone, regardless of "guilty" knowledge, it is part of the true description of what they do in having or attempting to have children.