As always well thought out and reasoned. Given the confusion created by the bizarre statements of Pope Francis and a media willfully obfuscating, this statement from the NCBC is much needed:
Beyond the issue of abortion, governments and public health experts may be justified in recommending that married couples delay childbearing temporarily in view of the great number of apparent risks associated with contracting Zika during pregnancy. Married couples should prayerfully assess any such recommendations. Pope Paul VI’s encyclical Humanae vitae clearly addresses this issue, teaching that “with regard to physical, economic, psychological and social conditions, responsible parenthood is exercised by those who prudently and generously decide to have more children, and by those who, for serious reasons and with due respect to moral precepts, decide not to have additional children for either a certain or an indefinite period of time” (HV, n. 10). Therefore, the couple should choose whether and to what extent they will accept such a recommendation, assessing all of their pertinent spousal duties and reliable medical facts: “The exercise of responsible parenthood requires that husband and wife, keeping a right order of priorities, recognize their own duties toward God, themselves, their families and human society” (HV, n. 10). Delaying pregnancy can be achieved through complete or periodic abstinence during the wife’s fertile period, which can be generally ascertained through bodily signs (natural family planning).You can read the whole thing at NCBC's website.
Humanae vitae also goes on to explain what “due respect to moral precepts” includes. Paul VI teaches that such respect excludes “any action which either before, at the moment of, or after sexual intercourse, is specifically intended to prevent procreation—whether as an end or as a means” (HV, n. 14). In response to the notion that contraception might be an acceptable lesser evil when compared to direct abortion, he further clarifies:
Neither is it valid to argue, as a justification for sexual intercourse which is deliberately contraceptive, that a lesser evil is to be preferred to a greater one. . . . Though it is true that sometimes it is lawful to tolerate a lesser moral evil in order to avoid a greater evil or in order to promote a greater good, it is never lawful, even for the gravest reasons, to do evil that good may come of it—in other words, to intend directly something which of its very nature contradicts the moral order, and which must therefore be judged unworthy of man, even though the intention is to protect or promote the welfare of an individual, of a family or of society in general. (HV, n. 14)This provides the foundation to answer a question increasingly being asked—whether it is ethical to use contraceptive methods, such as condoms, to reduce the likelihood of transmission of the Zika virus. Apart from the scientific questions about the actual effectiveness of condoms in disease prevention, using condoms to reduce the likelihood of Zika transmission amounts to directly intending contraceptive acts of intercourse as a means to a good end. It “deliberately frustrate[s] . . . the natural power and purpose” of marital intercourse (see CC, n. 54). In the case of a woman who is already pregnant, condom use could not have the effect of preventing pregnancy, but it would prevent a true marital act from taking place, which always involves a complete giving and receiving on the part of the husband and wife.
Some might also wonder about the use of contraceptive pills or intrauterine devices as a form of self-defense against the disease. This line of reasoning is invalid: hormonal contraceptives, IUDs, and morning-after pills do nothing to prevent sexual transmission of disease, but rather prevent the conception of a new human life or the implantation of an existing embryonic human being. Their use would amount to directly intending contraception or early abortion as a means of preventing potential birth defects. In other words, it would deliberately violate the unitive and procreative meanings of human self-giving in marital intimacy or purposefully destroy innocent human life, which are means that no good end can justify.