Presumably, the theory goes, since intercourse is likely to take place on the fringes of a woman's ovulation, any joining that happens in this period is more likely to be doomed than most. Therefore, if the Church is to be consistent, according to Bovens, it should outlaw NFP. (Well, he calls it the rhythm method, which is a complete, and probably deliberate, misnomer since that method hasn't been seriously used for decades.) “If you’re concerned about embryonic death,” Bovens says, “you’ve got to be consistent here and give up the rhythm method.” (Well, we did give up the rhythm method -- and replaced it with NFP.)
Anyway, here is a letter to the editor I've written to New Scientist, an Australian publication that carried the story about it:
The story on the "rhythm method" was farcical from the start. If you have a false premise, then the rest of your argument fails. In this case, no one is using the rhythm method anymore. This has long been replaced by any number of methods far more scientific in approach than rhythm ever was. Collectively, they are called Natural Family Planning. And, yes, from personal experience I can testify to its effectiveness -- at both postponing and acheiving pregnancy.
Beyond this, though, Bovens' position is absurd. The issue isn't the creation of embryos that then die naturally. That happens regularly and should cause no one any moral concern. The issue is whether or not the deaths of these embryos are deliberate. If they die a natural death, so be it. Contrary to Bovens' claims, the Catholic Church has never taught that the preservation of the embryo is the summum bonum.
However, if they're deliberately killed or killed because of the deliberate presence of a chemical known to make the womb hostile to new life, that's a completely different story. It is here that the moral agent has culpability.
Even if NFP does cause more embryos to die (which I think is highly doubtful), the couple are not liable for that, and Bovens should know that and no amount of moralizing on his part can change that fact.
It is at best reprehensible for Bovens to try to place guilt on couples who practice NFP because of this supposed finding. As much as I try, though, I cannot believe Bovens was really trying to help anyone along. It is clear from this one quote, "If you’re concerned about embryonic death, you’ve got to be consistent here and give up the rhythm method," that Bovens is trying to get in a jab at the Catholic Church. He fails miserably, leaving behind a stench of hypocritical moral superiority that reeks throughout the story -- and it is revolting.