The virtue which allows a human being to lead a sexually moral life is chastity, closely aligned with temperance, justice and charity. It should be kept in mind that chastity is a supernatural virtue, received at baptism, by the grace of God. From a human point of view it would be nice if we could take a pill to become chaste, and another pill to become docile to the Holy Spirit, but as it is these things require prayer, mortification and self-discipline. Anything that would tend to make the pleasure of sexuality an end in itself, separated from its procreative and unitive ends, opposes the virtue of chastity and is thus disordered. The moral life is lived through the virtues.

It is practically inevitable when proposing Natural Family Planning (NFP) to someone that the objection will be raised that there really isn’t any difference between natural and artificial methods of family planning – since, after all, the final objective for both is the prevention of pregnancy. This insight is flawed to the extent that the means to arrive at the proposed end is immoral. Thus, two men might have the same good motive to support their families, but since one does it by honest employment he grows in virtue, but the other man, resorting to unethical business practices, becomes more and more enmeshed in darkness.

The Catholic Church has repeatedly stated in the clearest terms that the use of artificial contraception is intrinsically evil, whereas the use of natural fertility methods is morally licit. Who can doubt that the widespread use of artificial contraception has led to significant problems in our culture including divorce and the breakdown in marriage, widespread promiscuity, fornication, and couples living together before marriage. Pope Benedict XVI, in Caritas in Veritate, notes a connection between the rejection of Humanae Vitae and the devaluation of life, saying:

“The Encyclical Humanae Vitae emphasizes both the unitive and the procreative meaning of sexuality, thereby locating at the foundation of society the married couple, man and woman, who accept one another mutually, in distinction and in complementarity: a couple, therefore, that is open to life. This is not a question of purely individual morality: Humanae Vitae indicates the strong links between life ethics and social ethics, ushering in a new area of magisterial teaching that has gradually been articulated in a series of documents, most recently John Paul II’s Encyclical Evangelium Vitae. The Church forcefully maintains this link between life ethics and social ethics, fully aware that “a society lacks solid foundations when, on the one hand, it asserts values such as the dignity of the person, justice and peace, but then, on the other hand, radically acts to the contrary by allowing or tolerating a variety of ways in which human life is devalued and violated, especially where it is weak or marginalized.”   (Caritas in Veritate, no. 15, footnotes omitted)

It has been said that “love is only only physiologically complete when it possesses an ethical value, when it is a virtue.” The virtue which counteracts a disordered sexuality is chastity. “Chastity is a virtue closely linked with the cardinal virtue of temperance. Possession of this virtue enables and necessitates the integration of man’s sexuality with his entire being: intellectual and spiritual. Chaste behavior leads to the self-possession necessary for self-donation, not only physically within marriage but also spiritually to God. Chastity is not achieved quickly nor is it attained easily. The ongoing pursuit of the virtue through grace and effort is in portion what makes its fruits so sweet” (quote by Stacey Holgate; see reference below).

Here, then, is the essential difference between NFP and artificial birth control – the relationship the two different methods of birth regulation have to the virtue of chastity. Natural Family Planning approaches marital sexuality – the moral venue for authentic sexuality – through the virtue of chastity, whereas artificial methods fail this test. Natural Family Planning is licit because, on a natural level, it works within the natural rhythms of a woman’s fertility consistent with the “procreative ordination of the body,” and, on a supernatural level, it works in harmony with the virtues of chastity and justice. The virtue of justice is met because NFP is to be used only in circumstances where there is a just reason (“well- grounded reasons”) not to procreate. The virtue of chastity is met because the regulation of eros is put under the control of a virtue which respects the moral dimension of the persons – that is, husband and wife.