It worked so well for for Catholics....

Ms. Taylor then went on to complain that there were an odd number of steps leading to her house. "I count them every time I enter or exit" she said "sometimes I go outside just to check. One day I counted them 37 times and each time there were an odd number of steps. Always five. Always." Ms. Taylor then turned in two circles, tugged her earlobe four times and stamped each foot twice.

What do you call a couple who practices "natural family planning"?....

Mom and dad?

Ah?

-> relevant link

Widdershins?

It only works widdershins.

That's exactly what came to mind when I was reading the article!

I have a very strong memory of my mother's best friend, an Irish Catholic by birth, coming over to our house with her new twin boys (circa 1967). She already had four children and was perhaps about 32. As she pushed the carriage up our front walk she sort of shouted: "how much more proof do you think my mother-in-law will need before she admits the rhythm method doesn't work".
I later learned her husband got a vasectomy after the birth of the twins.

Parents. I speak from experience.

We tried it for years in the 60's. By the time you subtract all days that are questionable, as well as a woman's monthly time-out, and add to that a few days when you are just too damn tired, there are only a few days left for hanky-panky. That may be why the method works well for spiritual and serious users -- they just don't have much sex.