Banquo:

You and I hold different positions on this issue, but your summary is a rather nice precis of the whole argument -- thank you.

An earlier poster -- Ironside? -- implied that a majority of conceptions do not result in the production of an adult human. I can only speak for the United States, but that is not accurate. Discounting abortion, Doctors estimate that about 1 conception in 3 fails to result in a birth (miscarriage, failure to implant, etc.) A very small percentage die during the birthing process. Another small percentage die from some illness or accident prior to adulthood. While this number is significant, it is not, however, a majority.