It may come as a surprise to non-Catholics that Catholics have a tendency to fight over Natural Family Planning--and no, it's not what you think. Sure, lots of people who say they're Catholic dissent from the Church's teachings about artificial birth control, and use it in spite of the sinful nature of this decision. I tend to proffer helpful Church resources to these people when I meet them, and to pray for them to turn away from birth control. So would most other orthodox Catholics I know.
No, the battle is between two different orthodox Catholic factions. Both agree emphatically and wholeheartedly with Catholic teaching on the subject of birth control. Both also agree that for Catholics who find it necessary to postpone the birth of their next child temporarily or even, as Paul VI mentions in Humanae Vitae, for an indefinite period, NFP is a morally licit option.
But the devil, as he always is, is in the details.
I want to make it clear that the two groups I'm describing below represent two extreme factions in this debate. There are many families who do not use NFP who do not at all fall into the first group described; there are many families who do use NFP who do not at all fall into the second group. But since the members of these two groups tend to be the loudest and most vocal ones whenever the issue of natural family planning is brought up for discussion, they're hard to overlook--and a lot of us orthodox, practicing Catholics end up somewhere in the middle of the argument, bewildered and wondering what's really going on here.
The first group of people are those who might be called the "Quiverful Providentialists," or QPs, for short. The QPs don't all have extremely large families, but it's not for lack of trying, as they'll be the first to tell you should the subject of NFP come up. They interpret the Church's teachings on the matter of marriage and family as meaning that, extraordinary circumstances alone excepted, the "default" mode for every marriage is to have, or try to have, as many children as is physically possible for the wife to bear. There are only two acceptable states for a faithful Catholic wife, for the QPs: pregnant, or trying to conceive. The third state of "no longer able to conceive" will come someday, of course, but in the meantime a woman's job is to maximize her fertility and add as many children as she can to surround the family table.
The QPs will admit, somewhat grudgingly, that the Church does allow NFP for "grave" reasons. (The other two words used in the context of the Church's teachings on NFP, "serious" and "just" reasons, seldom come up in the QP vocabulary--it's "grave" or nothing.) The QPs tend to discuss only two possible categories of grave reason: finances and the physical life/health of the mother. Their answer to the first question tends to focus on the fact that we live in America, the "richest country in the world," and that therefore means exist to allow people to have children even when they are suffering financial hardships. I have heard QPs discussing the various ways a family can continue to have children when there are limited funds, such as declaring bankruptcy in order to qualify for Medicaid, and taking advantage of various aid programs such as WIC, children's health insurance programs in various states, and other forms of welfare; thus the notion is presented that being prudent about one's economic circumstances is actually a "contraceptive" mentality, and that as long as there are charitable and government resources to help keep the family's basic needs supplied it is almost sinful to postpone a child using NFP under these sorts of circumstances.
The QPs answer to the second question is similar; I have been personally informed that in this country, with this country's medical resources, no condition exists which would really be a "good enough" reason for a woman not to become pregnant. If a woman is able to explain her medical condition in a way that satisfies this first objection, the next objection will be that she shouldn't trust the medical advice she has received unless a pro-life Catholic doctor has given it to her--all other doctors are just trying to scare her, and can't be trusted. Should she have spoken to pro-life and/or Catholic doctors, the next thing she is told is that perhaps if she trusts God, her medical condition will be miraculously resolved once she becomes pregnant--or, if it isn't, that she is being invited to become a mother/martyr like St. Gianna Molla. When all of that has been said, a stern warning in the form of the Cure of Ars' famous (and I believe, misunderstood) statement to the effect that women go to Hell for not having all the children God wanted them to have will be the final word on the subject; at this point the QP person seem to believe he/she has done his/her duty and can wash his/her hands of you in good conscience.
On the opposite side of this argument we can find the NFP cheerleaders, or Nfpteers. Again, just as not every family who decides not to use NFP is a QP, so to are there many NFP users who are not Nfpteers. The Nfpteer is the person who thinks that NFP is the source of most of the marital blessings out there, aside from one or two that may come from the sacramental nature of marriage itself. They believe that NFP is the sole reason that good Catholic couples are able to solve marital problems and stay married, that somehow the open communication NFP requires leads to an openness of communication and respect in all other areas of matrimony, that, if you'll forgive the phrase, "the family that charts together hearts together." While the Nfpteer may recognize that there are families out there who never use NFP but are still good Catholic families, they're almost as grudging about the idea as the QPs are toward the idea of NFP.
To someone they suspect of being on the QP side of things, the Nfpteer will often focus on the many "side-effect" benefits of NFP, ranging from the aforementioned communication to the depth of knowledge a woman gains about the mystery of her female and cyclic biology. Nfpteers may express the notion that nobody says you have to use NFP just to abstain or postpone children--why, if you want to have as many as possible, why wouldn't you want to use NFP to help with that? They may express the idea that a couple who doesn't use NFP may experience periods of satiety, when their supposed lack of self-control has a dampening effect on the mystery and romance of marital union. They may even start to hint about a lack of prudence, or to discuss the importance of focused types of parenting.
Some of the Nfpteers find that the number three has a near-religious significance--not three as in three total children, but three as in the "right" number of years to space each child from his or her next youngest sibling. They will point to pregnancy and nursing patterns among primitive women in support of the idea that God's real intention was for the female body to rest for three years between each birth; they will also cite various medical or sociological studies aimed at proving that three years between children is best for everybody--fathers, mothers, children. To the objection sometimes raised that this would tend to create smaller families, the Nfpteer will show that a woman of normal fertility who marries in her early twenties will still be quite capable of having anywhere from six to eight children, each three years from the other.
The QPs see the Nfpteers as sinfully lax in their ideas--what, is family spacing suddenly supposed to be a "grave reason"? The Nfpteers see the QPs as sinfully imprudent in their ideas--what, going on welfare constitutes responsible parenthood? Each side tends to caricature the other in arguments and discussions, and each side tends to get boiling mad at the representatives of the other. In the end, both the QPs and the Nfpteers are each secretly convinced that they, and they alone, understand what the Church really means in Her teachings on marital fecundity, NFP, and responsible parenthood.
Those of us who fall somewhere in between these two extremes are left to puzzle over the whole thing. To many of us, what the Church teaches seems to be both reasonably clear and abundant in wisdom and generosity--and both the QPs and the Nfpteers seem a little unbalanced on the subject. To say the least.