When I started tuning in to my body’s signals about about fertility, I was absolutely blown away by what I learned. I mean, how did I get to be a grown-ass, sexually-active adult woman without any understanding that the fluid that comes out of your vagina is indicative of where you are in your cycle? I don’t know, but I’m certainly not the only one who operated for the majority of her reproductive life with a serious deficit in basic fertility knowledge: I just explained cervical fluid to two of my friends, who were absolutely shocked. I don’t know why this information isn’t covered in basic sex ed or written about in all those omnipresent women’s mag articles on fertility and contraception. We’re educated about the menstrual cycle and the hormones that play into it, but I don’t think it’s common knowledge that you can really only get pregnant for roughly seven to 10 days each month. It certainly wasn’t for me.
Almost every conservative Catholic married woman knows this stuff.
The "hic" about fertility awareness is that you really should be a in a committed relationship (re: marriage) because openness to life is what it's about.
And that's probably why it's not more popular.
And another thing: FAM (that's the acronym it's known by) is slightly different than NFP, in that condoms are part of the plan.