Canon 1055 of the new Code presents matrimony as being directed to two ends: it is "by its nature ordered toward the good of the spouses and toward the procreation and education of offspring" ("indole sua naturali ad bonum coniugum atque ad prolis generationem et educationem ordinatum").
St. Thomas teaches that "unity pertains to fides, just as inseparability does to sacramentum" (In IV Sent., d. 31, q. 1, art. 2 ad 4). These words, when read in conjunction with those of canon 1056 - "The essential properties of marriage are unity and indissolubility" - , would seem to suggest that just as the "bonum sacramenti" and indissolubility are synomymous, so are the "bonum fidei" and unity.
The jurisprudence of church tribunals has constantly held that the marriage consent from which offspring is intentionally excluded ("bono prolis excluso") is null. A recent rotal Sentence coram Stankiewicz, in expressing this principle, says that it is the exclusion of the procreative element which vitiates the very object of matrimonial consent: "Since the procreative element enters the essence of matrimony and represents an essential component of the formal object of matrimonial consent, no one of the contracting parties can deliberately exclude it without thereby invalidating the marriage itself" (coram Stankiewicz, 29 October, 1987, n. 3).
The 1917 Code of Canon Law described matrimonial consent as that "act of the will by which each party gives and accepts a perpetual and exclusive right over the body, for acts which are of themselves suitable for the generation of children" (1917 Code: canon 1081, # 2.). The 1983 Code describes this consent in apparently very different terms: it is that "act of the will by which a man and a woman, through an irrevocable covenant, mutually give and accept each other in order to establish a marriage" (1983 Code: canon 1057, # 2. ).