Frankly, the spinning, rationalizations and justifications here would do Clinton proud.
But you're not circumventing anything with the rhythm method. The natural process IS a period of infertility. And as anyone whose tried it can tell you, I wouldn't place any large bets against conception occuring anyhow. The process isn't fool proof by any stretch, so couples are well aware that conception is still a reasonable possibility. Also, if the rhythm method was as reliable as you seem to think it is, no one would bother with condoms, end of story.
Frankly, the spinning, rationalizations and justifications here would do Clinton proud.
Touched a nerve? Sheesh. There's no law saying you have to be a Catholic. If you can come up with an argument that trumps 2000 years of Catholic theology, then go for it.