"If all of Alcorn’s 780 million pill users were to switch to the rhythm method, then these converts would be causing, in his own words, the deaths not of tens of thousands, but of millions of unborn children."
Bovens has pulled a switcheroo here. Alcorn referred to "780 pill cycles per year", not 780 million pill users. I hate to drag out the old 28-day cycle myth, but since we don’t know how long each pill user’s cycle would normally be, we have to guess based on averages. So, a 28-day cycle works out to about 13 cycles per woman per year. That works out to 60 million pill users per year, not 780 million.
Alcorn states that if even .01% of the 780 pill cycles per annum involves chemical abortion, the result could be 78,000 chemically induced abortions. What I do not know, and the FDA do not say, is how often emergency contraception (EC) acts by preventing implantation. Perhaps one of my astute readers can help out with some statistics. My instincts tell me that EC acts as an abortifacient more often that the Pill, since it is not taken in time to affect cervical mucus consistency and it will not always be taken in time to prevent ovulation. Then again, Bovens demonstrates well how wrong instincts can be. Dr. Whitty takes issue with using the .01% figure at all.
The article’s use of Alcorn is open to question. He proposed an “infinitesmal” small proportion (0.01%) of pill-use cycles resulting in a conception lost due to pill use, to provide a minimum statistic for purposes of illustration and contrast. Bovens takes Alcorn’s minimal estimate and uses it as if it were fact in regard to embryo loss on the combined oral contraceptive pill, so that his supposed “loss” with use of the rhythm method seems huge by comparison. What is known is that older formulations of the pill allowed breakthrough ovulation in 2-10% , (4,5) or 4.7% (6) of cycles, and about 27 cycles per 100 women per year in later studies (7). Progesterone preparations have higher ovulation rates, and the IUD still higher. Recording or calculating a ‘conception and loss rate’ for these cycles is another matter.
Having used what he believes to be sound reasoning to implicate NFP in avoidable embryo deaths, Bovens then entertains some possible pro-life responses. Since there’s little actual reasoning in his arguments, I’d just as soon skip his charicatures of pro-life rebuttals. However, since they involve subtle changes to his arguments and could easily stand on their own, I’ll briefly address them, if only to highlight his slight of hand.