"Serious motives, such as those which not rarely arise from medical, eugenic, economic and social so-called 'indications,' may exempt husband and wife from the obligatory, positive debt for a long period or even for the entire period of matrimonial life. From this it follows that the observance of the natural sterile periods may be lawful, from the moral viewpoint: and it is lawful in the conditions mentioned. If, however, according to a reasonable and equitable judgment, there are no such grave reasons either personal or deriving from exterior circumstances, the will to avoid the fecundity of their union, while continuing to satisfy to the full their sensuality, can only be the result of a false appreciation of life and of motives foreign to sound ethical principles."
Well, that's about as clear as mud. First of all, difficulties might not be rare, but they can still be rather uncommon. How do we interpret what Pius meant by "not rare"? Does "not rare" mean any given couple will encounter such difficulties many times? I doubt it. Does it mean that many couples will encounter them at least once?That seems reasonable. I only bring this point up because I know some people read "not rare" to mean that serious/grave reasons are common. If you spend any time at all dealing with probability and statistics, you'll realize that "rare" and "not rare" are very vague concepts that need to be represented by numbers to be meaningful. Saying that difficulties "not rarely arise" only tells us that they might not be statistical outliers, which doesn't tell us much.
Secondly, medical, eugenic (!), economic, and social are very broad categories of "indication". How are we to determine which subcategories are licit?!? Granted, when the Vatican speaks, what is said should pertain to the universal Church, but surely there are some scenarios that are objectively licit, but under some subjective circumstances might be illicit (or vice versa).
Thirdly, whose "reasonable and equitable judgment" is to be employed? Given the context, I am inclined to believe he was referring to the judgment of midwives. If that is indeed the case, I would very much like to know what criteria they were supposed to use to determine if motives were sufficiently serious. Also, since midwifery is no longera commonly practiced art these days (at least in the West), I'd like to know what apostolate, having similar or identical powers to judge and guide, has taken its place.
Lastly, since when does the Church support eugenics? I can only assume Pius meant something different by that word than the definition commonly accepted today. If someone could explain what he meant, I'd be much obliged.
One thing that is somewhat clear is that the mere existence of "serious" or "grave" reasons does not automatically make periodic abstinence licit, for Pius says that such reasons "may exempt husband and wife from the obligatory, positive [marital] debt" [emphasis mine].
"Perhaps you will now press the point, however, observing that in the exercise of your profession you find yourselves sometimes faced with delicate cases, in which, that is, there cannot be a demand that the risk of maternity be run, a risk which in certain cases must be absolutely avoided, and in which as well the observance of the agenesic periods either does not give sufficient security, or must be rejected for other reasons. Now, you ask, how can one still speak of an apostolate in the service of maternity?"
"If, in your sure and experienced judgment, the circumstances require an absolute 'no,' that is to say, the exclusion of motherhood, it would be a mistake and a wrong to impose or advise a 'yes.' Here it is a question of basic facts and therefore not a theological but a medical question; and thus it is in your competence. However, in such cases, the married couple does not desire a medical answer, of necessity a negative one, but seeks an approval of a 'technique' of conjugal activity which will not give rise to maternity. And so you are again called to exercise your apostolate inasmuch as you leave no doubt whatsoever that even in these extreme cases every preventive practice and every direct attack upon the life and the development of the seed is, in conscience, forbidden and excluded, and that there is only one way open, namely, to abstain from every complete performance of the natural faculty. Your apostolate in this matter requires that you have a clear and certain judgment and a calm firmness."
For some women, pregnancy and/or childbirth could be fatal. How should they procede? Well, the answer seems to be that they should entirely refrain from the marital act. NFP is not perfect birth control. In fact, any such method might be forbidden by the Church as being hostile to fertility. Therefore, such an at-risk woman might unwittingly conceive and endanger her life and/or the life of her child.I think this teaching could also be applied the AIDS epidemic. The solution to stopping AIDS isn't condoms, it's continence (the A and B of ABC). The maxim "If you can't do the time, don't do the crime" applies here. If you cannot or will not accept the potential natural consequence of intercourse, pregnancy, you should not engage in it. Taking this one step further, I am wondering why the Church does not advise couples not ready for a/another child to abstain from intercourse completely until they are ready (that is, until they no longer have serious/grave reason to avoid conception).
"It will be objected that such an abstention is impossible, that such a heroism is asking too much. You will hear this objection raised; you will read it everywhere. Even those who should be in a position to judge very differently, either by reason of their duties or qualifications, are ever ready to bring forward the following argument: 'No one is obliged to do what is impossible, and it may be presumed that no reasonable legislator can will his law to oblige to the point of impossibility. But for husbands and wives long periods of abstention are impossible. Therefore they are not obliged to abstain; divine law cannot have this meaning.'"
"In such a manner, from partially true premises, one arrives at a false conclusion. To convince oneself of this it suffices to invert the terms of the argument: "God does not oblige anyone to do what is impossible. But God obliges husband and wife to abstinence if their union cannot be completed according to the laws of nature. Therefore in this case abstinence is possible." To confirm this argument, there can be brought forward the doctrine of the Council of Trent, which, in the chapter on the observance necessary and possible of referring to a passage of St. Augustine, teaches: 'God does not command the impossible but while He commands, He warns you to do what you can and to ask for the grace for what you cannot do and He helps you so that you may be able'."
"Do not be disturbed, therefore, in the practice of your profession and apostolate, by this great talk of impossibility. Do not be disturbed in your internal judgment nor in your external conduct. Never lend yourselves to anything which is contrary to the law of God and to your Christian conscience! It would be a wrong towards men and women of our age to judge them incapable of continuous heroism. Nowadays, for many a reason,—perhaps constrained by dire necessity or even at times oppressed by injustice—heroism is exercised to a degree and to an extent that in the past would have been thought impossible. Why, then, if circumstances truly demand it, should this heroism stop at the limits prescribed by the passions and the inclinations of nature? It is clear: he who does not want to master himself is not able to do so, and he who wishes to master himself relying only upon his own powers, without sincerely and perseveringly seeking divine help, will be miserably deceived."
It is an insult to God to suggest that heroic continence is impossible. Christ Himself said, "With men it is impossible, but not with God; for all things are possible with God" (Mark 10:27) and "Have faith in God.Truly, I say to you, whoever says to this mountain, 'Be taken up and cast into the sea,' and does not doubt in his heart, but believes that what he says will come to pass, it will be done for him.Therefore I tell you, whatever you ask in prayer, believe that you have received it, and it will be yours." (Mark 11:23-24). He also said, "Ask, and it will be given you; seek, and you will find; knock, and it will be opened to you.For every one who asks receives, and he who seeks finds, and to him who knocks it will be opened." (Matthew 7:7-8) The suggestion of impossibility is also an insult to humanity because people have been heroic in greater things than this. Of course, as Christians we should be helping people be heroic. As St. James says, "If a brother or sister is ill-clad and in lack of daily food, and one of you says to them, 'Go in peace, be warmed and filled,' without giving them the things needed for the body, what does it profit?" Amen. Examples of ways to help promote a culture of life include working at a crisis pregancy center and assisting a stay-at-home mom with daily chores.