The distinguished Evangelical Protestant theologian, philosopher, and apologist, Norman L. Geisler devotes “Appendix 4” of his book, Christian Ethics: Contemporary Issues & Options, Second Edition (Baker Academic, 2010), pp. 396-405 to defending the moral permissibility of birth control over the Catholic rejection of “artificial types” (p. 396). He asserts that one reason among several that Catholics reject “artificial birth control” is the idea that sex is for procreation only (see pp. 397-398). But this is a straw man. No Catholic teaching or Catholic theologian affirms this view (Although St. Augustine did affirm it, his position is much more nuanced than is usually thought).
Pope Paul VI’s 1968 encyclical, Humanae vitae, for example, speaks of “the unitive significance and the procreative significance which are both inherent to the marriage act.” So, contra Geisler, sex is for both procreation and union (And “union” here in Catholic teaching can encompass what Geisler observes are other rightful purposes of sex: “unification, recreation, and communication in the context of marriage” [p. 405; see also pp. 400-401]). The moral malice of contraception lies precisely in the fact that it is the kind of act that not only impedes new human life from being generated, but also impedes the “one-flesh” union (to be) actualized in spousal intercourse.
I would also note that among the many other errors Geisler makes about Catholic teaching on birth control, two stand out (see pp. 398-399, footnote 2) – and they are quite common. First, he refers to the Catholic acceptance of the “rhythm method”, when in actual fact it’s no longer this outdated and often unreliable method that the Church promotes, but natural family planning (NFP). There’s a big difference, moral as well as anthropological, between them (See Pope John Paul II, Familiaris consortio, no. 32). The chief moral difference is the fact that the free choice to use contraception involves a choice to engage in sexual intercourse that is anti-procreative, while the free choice to use NFP involves a choice to engage in sexual intercourse that is non-procreative. There’s a significant moral difference between choosing to realize a good, choosing not to realize a good, and choosing to do something against a good (Note: Even when spouses do not intend to act against the procreative good – say, when using a condom in order to prevent the transmission of a disease – they do in fact act against the unitive good of sexual intercourse as well as close the sexual act to the procreative good).
Second, Geisler seems to think that the Church’s moral teaching rests on the distinction between methods that are “natural” and methods that are “artificial.” If the former, they are morally acceptable; if the latter, they are not. Geisler rightly rejects this argument. And so do most Catholics who support the teaching, including myself. Nowhere in Church teaching on birth control is this distinction morally decisive (Of course, natural methods come with many benefits and none of the many bad side-effects of the artificial methods, e.g., to health and the environment). In sum, the Catholic Church condemns contraception as always wrong, while she accepts NFP when practiced uprightly by spouses, that is, for serious reasons and good ends.
Given the truth that Catholicism does not teach that procreation is the only purpose of sex, Geisler’s response to what he calls “the Roman Catholic view limiting sex to procreation” (see pp. 400-401), totally misses the mark. He’s arguing against a position that the Church simply does not hold. If Geisler decides someday to publish a third edition of what is, in some ways, a fine ethics book – although I disagree with many of his other views – I would suggest that he first correct these serious errors.