Our inquiry centers on the nature of and relationship between sex and marriage. As our culture has become increasingly uncertain about what marriage is, serious questions have arisen about what makes sex valuable – what sex should be for – and how sex should be related to marriage. Is sex merely a pleasurable activity that people should enjoy whenever it is convenient, provided they avoid coercion, deception, disease, and undesired pregnancy? Or does sex have more inherent significance so that it should be reserved only for those with whom one has an ongoing, loving relationship, or even a marital bond? In this chapter, we examine the inherent significance of sexual acts and their relationship to marriage and procreation. In marital intercourse, husband and wife embody and express their multileveled union that is marriage. By choosing to embody their marital union in a sexual act, spouses give themselves to each other, for by this act, each intends the fulfillment of the other, and intends this act as part of the sharing of himself or herself with the other. Marital intercourse between spouses consummates or renews their marital union and so is itself a participation in – not a mere sign of or extrinsic means to – a basic human good, namely, the basic good of marriage itself.

Someone might claim that although marital intercourse does realize a distinctive good, nonmarital sex can realize other goods, even if on a lesser scale. Marital sex (it might be argued) might realize an exalted good, but it does not follow that every sexual act must realize this benefit in order to be morally right or permissible. Perhaps consensual sexual acts (between, say, strangers) done simply for the sake of pleasure, or sexual acts done to express or signify nonmarital, romantic relationships, are worthwhile and morally permissible, even though their benefits are less profound than the good of marriage.