Dubium:
Should those spouses be reprehended who make use of marriage only on those days when (in the opinion of some doctors) conception is impossible?
Response: After mature examination, we have decided that such spouses should not be disturbed [or disquieted], provided they do nothing that impedes generation
~ Question by Bishop of Amiens, France, 1853 AD, response by Sacred Penitentiary, quoted in J. Montánchez, Teología Moral [Buenos Aires, 1946], p. 654.
Dubium:
Whether it is licit to make use of marriage only on those days when it is more difficult for conception to occur?
Response: Spouses using the aforesaid method are not to be disturbed; and a confessor may, with due caution, suggest this proposal to spouses, if his other attempts to lead them away from the detestable crime of onanism have proved fruitless.
~ June 16, 1880 AD, reply of the Sacred Penitentiary to confessors in order to discourage onanism (withdrawal). The editorial notes in Denzinger indicate that this decision was made public the following year (1881) in the respected French journal Nouvelle Revue Théologique, and in Rome itself in 1883 in the Vatican-approved series Analecta Iuris Pontificii.
Regarding the Exclusive Use of the Infertile Period
53. And now, Venerable Brethren, we shall explain in detail the evils opposed to each of the benefits of matrimony. First consideration is due to the offspring, which many have the boldness to call the disagreeable burden of matrimony and which they say is to be carefully avoided by married people not through virtuous continence (which Christian law permits in matrimony when both parties consent) but by frustrating the marriage act. (emphasis added)
~Castii Connubii, Pope Pius XI, 1930
59. Holy Church knows well that not infrequently one of the parties is sinned against rather than sinning, when for a grave cause he or she reluctantly allows the perversion of the right order. In such a case, there is no sin, provided that, mindful of the law of charity, he or she does not neglect to seek to dissuade and to deter the partner from sin. Nor are those considered as acting against nature who in the married state use their right in the proper manner although on account of natural reasons either of time or of certain defects, new life cannot be brought forth. For in matrimony as well as in the use of the matrimonial rights there are also secondary ends, such as mutual aid, the cultivating of mutual love, and the quieting of concupiscence which husband and wife are not forbidden to consider so long as they are subordinated to the primary end and so long as the intrinsic nature of the act is preserved. (emphasis added)
~Castii Connubii, Pope Pius XI, 1930
Dubium:
Whether the practice is licit in itself by which spouses who, for just and grave causes, wish to avoid offspring in a morally upright way, abstain from the use of marriage – by mutual consent and with upright motives – except on those days which, according to certain recent [medical] theories, conception is impossible for natural reasons.
Response: Provided for by the Response of the Sacred Penitentiary of June 16, 1880.
~ July 20, 1932 AD, Sacred Penitentiary under Pope Pius XI, two years after the release of Casti Connubii, Roman documentary journal Texta et Documenta, series theologica (vol. 25 [1942], p. 95).
Birth control
Today, besides, another grave problem has arisen, namely, if and how far the obligation of being ready for the service of maternity is reconcilable with the ever more general recourse to the periods of natural sterility the so-called "agenesic" periods in woman, which seems a clear expression of a will contrary to that precept.
You are expected to be well informed, from the medical point of view, in regard to this new theory and the progress which may still be made on this subject, and it is also expected that your advice and assistance shall not be based upon mere popular publications, but upon objective science and on the authoritative judgment of conscientious specialists in medicine and biology. It is your function, not the priest's, to instruct the married couple through private consultation or serious publications on the biological and technical aspect of the theory, without however allowing yourselves to be drawn into an unjust and unbecoming propaganda. But in this field also your apostolate demands of you, as women and as Christians, that you know and defend the moral law, to which the application of the theory is subordinated. In this the Church is competent.
It is necessary first of all to consider two hypotheses. If the application of that theory implies that husband and wife may use their matrimonial right even during the days of natural sterility no objection can be made. In this case they do not hinder or jeopardize in any way the consummation of the natural act and its ulterior natural consequences. It is exactly in this that the application of the theory, of which We are speaking, differs essentially from the abuse already mentioned, which consists in the perversion of the act itself. If, instead, husband and wife go further, that is, limiting the conjugal act exclusively to those periods, then their conduct must be examined more closely.
Here again we are faced with two hypotheses. If, one of the parties contracted marriage with the intention of limiting the matrimonial right itself to the periods of sterility, and not only its use, in such a manner that during the other days the other party would not even have the right to ask for the debt, than this would imply an essential defect in the marriage consent, which would result in the marriage being invalid, because the right deriving from the marriage contract is a permanent, uninterrupted and continuous right of husband and wife with respect to each other.
However if the limitation of the act to the periods of natural sterility does not refer to the right itself but only to the use of the right, the validity of the marriage does not come up for discussion. Nonetheless, the moral lawfulness of such conduct of husband and wife should be affirmed or denied according as their intention to observe constantly those periods is or is not based on sufficiently morally sure motives. The mere fact that husband and wife do not offend the nature of the act and are even ready to accept and bring up the child, who, notwithstanding their precautions, might be born, would not be itself sufficient to guarantee the rectitude of their intention and the unobjectionable morality of their motives.
The reason is that marriage obliges the partners to a state of life, which even as it confers certain rights so it also imposes the accomplishment of a positive work concerning the state itself. In such a case, the general principle may be applied that a positive action may be omitted if grave motives, independent of the good will of those who are obliged to perform it, show that its performance is inopportune, or prove that it may not be claimed with equal right by the petitioner—in this case, mankind.
The matrimonial contract, which confers on the married couple the right to satisfy the inclination of nature, constitutes them in a state of life, namely, the matrimonial state. Now, on married couples, who make use of the specific act of their state, nature and the Creator impose the function of providing for the preservation of mankind. This is the characteristic service which gives rise to the peculiar value of their state, the bonum prolis. The individual and society, the people and the State, the Church itself, depend for their existence, in the order established by God, on fruitful marriages. Therefore, to embrace the matrimonial state, to use continually the faculty proper to such a state and lawful only therein, and, at the same time, to avoid its primary duty without a grave reason, would be a sin against the very nature of married life.
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 tile full their sensuality, can only be the result of a false appreciation of life and of motives foreign to sound ethical principles.
~ Address to Midwives, Given by His Holiness Pope Pius XII, 29 October 1951
11. The sexual activity, in which husband and wife are intimately and chastely united with one another, through which human life is transmitted, is, as the recent Council recalled, "noble and worthy.'' (11) It does not, moreover, cease to be legitimate even when, for reasons independent of their will, it is foreseen to be infertile. For its natural adaptation to the expression and strengthening of the union of husband and wife is not thereby suppressed. The fact is, as experience shows, that new life is not the result of each and every act of sexual intercourse. God has wisely ordered laws of nature and the incidence of fertility in such a way that successive births are already naturally spaced through the inherent operation of these laws.
~Humanae Vitae, Pope Pius VI, 1968
16. Now as We noted earlier (no. 3), some people today raise the objection against this particular doctrine of the Church concerning the moral laws governing marriage, that human intelligence has both the right and responsibility to control those forces of irrational nature which come within its ambit and to direct them toward ends beneficial to man. Others ask on the same point whether it is not reasonable in so many cases to use artificial birth control if by so doing the harmony and peace of a family are better served and more suitable conditions are provided for the education of children already born. To this question We must give a clear reply. The Church is the first to praise and commend the application of human intelligence to an activity in which a rational creature such as man is so closely associated with his Creator. But she affirms that this must be done within the limits of the order of reality established by God.
If therefore there are well-grounded reasons for spacing births, arising from the physical or psychological condition of husband or wife, or from external circumstances, the Church teaches that married people may then take advantage of the natural cycles immanent in the reproductive system and engage in marital intercourse only during those times that are infertile, thus controlling birth in a way which does not in the least offend the moral principles which We have just explained. (20)
Neither the Church nor her doctrine is inconsistent when she considers it lawful for married people to take advantage of the infertile period but condemns as always unlawful the use of means which directly prevent conception, even when the reasons given for the later practice may appear to be upright and serious. In reality, these two cases are completely different. In the former the married couple rightly use a faculty provided them by nature. In the later they obstruct the natural development of the generative process. It cannot be denied that in each case the married couple, for acceptable reasons, are both perfectly clear in their intention to avoid children and wish to make sure that none will result. But it is equally true that it is exclusively in the former case that husband and wife are ready to abstain from intercourse during the fertile period as often as for reasonable motives the birth of another child is not desirable. And when the infertile period recurs, they use their married intimacy to express their mutual love and safeguard their fidelity toward one another. In doing this they certainly give proof of a true and authentic love.
~Humanae Vitae, Pope Pius VI, 1968
Right conscience is true interpreter
3. The use of the infertile periods for conjugal union can be an abuse if the couple, for unworthy reasons, seeks in this way to avoid having children, thus lowering the number of births in their family below the morally correct level. This morally correct level must be established by taking into account not only the good of one's own family, and even the state of health and the means of the couple themselves, but also the good of the society to which they belong, of the Church, and even of all mankind.
The Encyclical Humanae Vitae presents responsible parenthood as an expression of a high ethical value. In no way is it exclusively directed to limiting, much less excluding, children. It means also the willingness to accept a larger family. Above all, according to Humanae Vitae, responsible parenthood implies "a deeper relationship with the objective moral order instituted by God—the order of which a right conscience is the true interpreter" (HV 10).
~ Wednesday audience, John Paul II, 5 September 1984
6. According to the criterion of this truth, which should be expressed in the language of the body, the conjugal act signifies not only love, but also potential fecundity. Therefore it cannot be deprived of its full and adequate significance by artificial means. In the conjugal act it is not licit to separate the unitive aspect from the procreative aspect, because both the one and the other pertain to the intimate truth of the conjugal act. The one is activated together with the other and in a certain sense the one by means of the other. This is what the Encyclical teaches (cf. HV 12). Therefore, in such a case the conjugal act, deprived of its interior truth because it is artificially deprived of its procreative capacity, ceases also to be an act of love.
~ Wednesday audience, John Paul II, 22 August 1984