It is often contended that if it is morally right for married couples to avoid conception by having intercourse during the infertile period of the wife's ovulation cycle, then it must be morally right to do so with contraceptive sex, especially if the same reasons are involved. Such reasoning ultimately reduces the procreative meaning of the conjugal act to procreation.
However, the moral difference between the Church's view of marital intercourse and the contraceptive view does not seem to be based on whether or not a possible procreation is prevented. The views differ because the conjugal act (fertile or infertile) is an act in fulfillment of a natural human inclination to procreate, and contraceptive sex is an act in which that tendency has been deliberately frustrated. It will be argued here that this distinction is helpful for a proper understanding of Humanae Vitae, as well as for resolving the confusion over the difference between conjugal sex and contraceptive sex.
Confusion in the issue can arise from an imprecision in our understanding and use of some key terms in Humanae Vitae and parallel terms in other Church documents. A review of these critical terms regarding the transmission of human life provides a basis upon which to distinguish the natural human inclination or tendency toward procreation from the generative process of procreation in Humanae Vitae.
For example, the term "procreation" is taken to mean the generation of human life, while "procreative" (procreationis) is a word describing the natural inclination of the conjugal act towards the generation of human life. In its procreative meaning the conjugal act is said to have an ordination (ordinem) to the supreme responsibility of parenthood (12). Gaudium et Spes also speaks of the institution of marriage and married love as being ordered to procreation (48;50). The conjugal act is therefore regarded as an act of a specific human inclination or tendency. The terms "fecund" or "fertile" (fecunditatem) and "infecund" or "infertile" (infecundi) refer respectively to the fertile and infertile periods of the wife's ovulation cycle (Humanae Vitae, 16). Humanae Vitae also describes conjugal love itself as fecund or creative of life (fecundus) (9). The love of the conjugal act is fecund in that the love between the spouses expressed in and through the act is inclined and ordered toward the generation of new human life.
Donum Vitae also reaffirms the essential end-oriented (i.e., teleological) nature of the conjugal act (II, B, 4) particularly in its reference to the "proper perfection" (perfectione propria) of the generation of the human person as being the result and fruit of a conjugal act (II, B, 5). This term signifies a fulfillment. It refers to the fulfillment of the teleological activity of the generation of the human person, who is caused by a particular conjugal act of the parents. In other words, it is intrinsic to the nature of the conjugal act that it tend toward procreation, which implies that part of what it means to be a human person is to have been generated by a conjugal act of the parents.
The moral norm of Humanae Vitae states that "in any use whatever of marriage there must be no impairment of its natural capacity to procreate human life [ ... quilibet matrimonii usus ad vitam humanam procreandam per se destinatus permaneat]" (H.V. #11,). The natural capacity or tendency of each and every conjugal act is precisely what must be preserved according to its procreative meaning. This reproductive inclination is a tendency toward procreation which, if rendered impossible by the result of contraception, thwarts the inclination of the conjugal act, i.e., its procreative meaning. But an inclination is not the same as its result or end. A tendency gives rise to activity for an end. If the natural human tendencies are unimpeded, they lead to activities which may bring about the ends of our human nature and powers.
If it is the inclination of our reproductive powers which must be fulfilled in and through the conjugal act, then the procreative meaning of the conjugal act cannot be reserved only for the "fertile act of marital intercourse"; and the infertile act of marital intercourse cannot be limited only to its unitive meaning. Such a view assumes a biologistic sense of the procreative meaning of the conjugal act (cf. "The Rhythm Method: an Upbeat Update," Ethics & Medics, July 1991, p. 2). On the contrary, both the fertile and infertile acts of marital intercourse are procreative, because both, under the right conditions, are acts in fulfillment of a natural tendency. This tendency, as constitutive of human nature, does not and cannot retreat during the infertile period of the ovulation cycle, postmenopause, and infertility. The teaching on the procreative meaning of the conjugal act in Humanae Vitae is invalid if it cannot apply to naturally infertile sex. The two meanings of the conjugal act do not apply differently in different situations. If the two meanings are said to be inseparably connected, then one cannot be fostered without the other.
The language of "openness" to procreation obfuscates the telic structure of the moral norm of Humanae Vitae which states that the conjugal act must (depending on the translation) remain "aimed at" (destinatus), or not be an "impairment of its natural capacity" for, procreating human life. There is an important conceptual difference between "aimed at" and "open to." To be "open" in this context is to be open to or to accept something specific. The document does not state that the conjugal act is to be open to the possible conception of a person. Rather, the moral norm of Humanae Vitae obliges the spouses to maintain the teleological nature of their conjugal union towards procreation as its end. It does not oblige them to make their conjugal act, simply by a choice, "open" to or accepting of the specific possibility of the conception of an individual person.
Contraception is morally prohibited by Humanae Vitae because an act of contraception alters the very nature of the conjugal act itself. It is not prohibited merely because of the choice to use contraception, a choice to close off the conception of a possible person. Contraception is prohibited because what is being done radically alters and misdirects the teleological nature of the conjugal union. The moral difference between contraceptive and conjugal sex is not only a difference of choices but of acts chosen. This is most evident in section 13 of Humanae Vitae. In that section, both the telic nature of the conjugal act and its use in the moral evaluation of contraception are evident. Contraception is considered morally wrong by Humanae Vitae because it is an attempted domination over, and redirecting of, the sexual faculties whose very nature is concerned with "the generation of life, of which God is the source" (13). This section of Humanae Vitae tells us that contraception impairs the capacity to transmit life, thereby contradicting the very nature of man and woman, their marital relationship, and the plan of God (13).
Whatever similarities there may be between the reasons for contraceptive sex and conjugal sex, one type of act obstructs the reproductive tendency of the particular act, and the other is an act in fulfillment of the tendency (cf. Humanae Vitae #16). This latter reason is why sex according to natural family planning is a morally good kind of act, not because, as is often assumed, it possesses an acceptable failure rate, in this way grounding the "openness" of the conjugal act to the conception of a possible baby. But the goodness of an act is not simply determined by the kind of good act that it is; its circumstances must also be right. The particular end intended is a circumstance of what we do. If one engages in the conjugal act only during infertile periods with the intention of never having children or not having children when there are no serious reasons not to, then the fact that the act is otherwise morally good in kind does not make that conjugal act good. It would still be defective in its intended end and therefore morally wrong.
Humanae Vitae does not define contraception and conjugal sex only in terms of choices and intended ends. These are individual steps and circumstances of the two acts which alone cannot determine the moral difference of the acts. The essential difference between the acts for Humanae Vitae lies in the fact that conjugal sex under the right circumstances fulfills the finality of the conjugal act and contraceptive sex contravenes that finality under any and all circumstances. Only a return to the teleological approach of the teaching in Humanae Vitae will show the real difference between conjugal sex and contraceptive sex.