The teaching of Humanae Vitae is not limited to the topic of contraception within marriage. In Humanae Vitae, the Magisterium condemns contraception as intrinsically evil and always gravely immoral, regardless of marital state. “Just as man does not have unlimited dominion over his body in general, so also, and with more particular reason, he has no such dominion over his specifically sexual faculties, for these are concerned by their very nature with the generation of life, of which God is the source.” [Humanae Vitae 13]. The reason that contraception is immoral is that the sexual faculties of human persons are “concerned by their very nature with the generation of life.” So it is the nature of the sexual faculty that is contradicted by contraception, not specifically or solely the marital meaning of sexual acts.
The Magisterium has repeatedly condemned the use of contraception outside of marriage: Contraception and Heresy — Part 2. And the Latin text of Humanae Vitae as well as other documents in no way supports the claim that the condemnation of contraception is limited to its use in marriage only: Contraception and Heresy — Part 3.
Humanae Vitae also condemns direct abortion and direct sterilization: “We are obliged once more to declare that the direct interruption of the generative process already begun and, above all, all direct abortion, even for therapeutic reasons, are to be absolutely excluded as lawful means of regulating the number of children. Equally to be condemned, as the magisterium of the Church has affirmed on many occasions, is direct sterilization, whether of the man or of the woman, whether permanent or temporary.” [Humanae Vitae 14]. Notice that direct abortion is not justified “even for therapeutic reasons”. Why? It is because intrinsically evil acts are never justified by the reason (or purpose or intended end) of the act.
Therefore, contraception is also not justified for a therapeutic or medical reason — especially when it is abortifacient contraception. The teaching of Humanae Vitae that direct abortion is not justified “even for therapeutic reasons” necessarily implies that abortifacient contraception is likewise not justified for a therapeutic or medical reason, since abortifacient contraception is a type of direct abortion.
But what most people do not realize is that the teaching of Humanae Vitae on sexual acts necessarily implies that the only moral sexual act is natural marital relations open to life.
First of all, sex outside of marriage is always gravely immoral: “husband and wife, through that mutual gift of themselves, which is specific and exclusive to them alone” [Humanae Vitae 8].
Then, too, the separation of the procreative and unitive meanings of sexual intercourse is always gravely immoral:
“This particular doctrine, often expounded by the magisterium of the Church, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act. The reason is that the fundamental nature of the marriage act, while uniting husband and wife in the closest intimacy, also renders them capable of generating new life—and this as a result of laws written into the actual nature of man and of woman. And if each of these essential qualities, the unitive and the procreative, is preserved, the use of marriage fully retains its sense of true mutual love and its ordination to the supreme responsibility of parenthood to which man is called.” [Humanae Vitae 12].
Contraception violates “laws written into the actual nature of man and of woman”. And so contraception is immoral, even outside of marriage.
But notice that this teaching on separation implies that the thwarting of the procreative meaning, via contraception, in an otherwise natural sexual act, does not entirely deprive the act of its unitive meaning. The meanings are said to be separated by contraception because the unitive meaning remains present (though it is undoubtedly injured by the absence of the procreative meaning).
Furthermore, the teaching of Humanae Vitae on the marital, unitive, and procreative meaning of sexual intercourse implies that all unnatural sexual acts are intrinsically evil and always gravely immoral, even within marriage. For “that procreative finality” must be present in “each single act,” not merely in one act out of several, not merely in a subset of sexual acts [Humanae Vitae 3].
“The Church, nevertheless, in urging men to the observance of the precepts of the natural law, which it interprets by its constant doctrine, teaches that each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life.” [Humanae Vitae 11].
It is therefore abundantly clear from the teaching of Humanae Vitae that each and every sexual act in a marriage must be that type of act inherently ordered toward both the procreative and unitive meanings. Yet unnatural sexual acts are not so ordered. They are not ordered toward procreation, as they are not the type of sexual act inherently capable of procreation. And they are not truly unitive, even if there is a mere base type of union of body parts, because it is not the type of sexual union ordained by God.
Thus, each sexual act between husband and wife must be considered as to its morality on its own. An unnatural sexual act, with or without climax, is not justified by occurring within the same time frame, or within the same set of acts, as a natural sexual act. Each and every sexual act must be marital, unitive, and procreative, in order to avoid grave sin.
Many Catholic teachers and leaders are teaching grave errors on abortion, abortifacient contraception, contraception, and unnatural sexual acts. They are doing grave harm to the Sacrament of Marriage and to the souls of the men and women whom they lead astray. And they are also complicit in the deaths of many prenatals, since they justify and encourage the use of abortifacient contraception, while sexually active, for therapeutic reasons.
Therefore, “married persons who, to prevent conception or procure abortion, have recourse to medicine, are guilty of a most heinous crime nothing less than wicked conspiracy to commit murder.” [Catechism of Trent].
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