The Church has always professed that Mary was a virgin “ante partum, in partu, et post partum,” i.e., before birth, during birth, and after the birth of Christ. Mary conceived Jesus in her womb “by the power of the Holy Spirit” without loss of her virginity. She remained a virgin in giving birth to Jesus; His miraculous birth did not diminish her virginal integrity but sanctified it (Vatican II, Lumen Gentium, no. 57). Following the birth of Jesus, Mary remained a virgin for the rest of her earthly life, until such time as she was taken body and soul into heaven, where she reigns as Queen ( Lumen Gentium, no. 59).
In one sense, Mary’s virginity postpartum (after birth) is the easiest aspect of Mary’s virginity to accept, inasmuch as her virginity ante partum and in partu required a miracle, whereas virginity postpartum, while granting the first two aspects, merely means that Mary remained a virgin (and consequently had no more children) after the birth of Christ.
In another sense, virginity postpartum can be the most difficult aspect to explain, inasmuch as (1) those who would reduce divine Revelation to Scripture alone cannot find evidence to support this contention in the New Testament, and (2) there are New Testament passages that seem to suggest that Mary was not in fact continent after Jesus’ birth. Without a proper understanding of the sources of Revelation, the first point cannot be overcome, because indeed it is true that a compelling case for Mary’s Perpetual Virginity cannot be made explicit by Scripture alone. However, for the confused Catholic and curious Protestant alike, it is important to demonstrate that this Church teaching is not in conflict with the inspired text, lest Mary’s Perpetual Virginity needlessly serve as a stumbling block for one who rightly venerates Sacred Scripture. In other words, it must be shown that a Church teaching firmly rooted in Tradition (i.e., the oral word of God) and proposed by the Magisterium does not—at minimum—contradict the witness of Scripture. If this cannot be done satisfactorily, the Catholic view of divine Revelation lacks plausibility.
Mary’s virginity postpartum, while not explicitly taught in Scripture, is repeatedly taught by the Latin, Greek, and Syriac Fathers. Outstanding among the patristic sources is St. Jerome’s zealous treatise On the Perpetual Virginity of the Blessed Mary Against Helvidius (383 A.D.), which not only affirms the teaching but specifically addresses the objections against Mary’s virginity postpartum that are typically raised in Protestant circles even today.
The following statement comes from Pope St. Siricius (circa 392 A.D.), in the course of approving the refutation of a certain Bonosus, who had asserted that Mary had other children:
“We surely cannot deny that you were right in correcting the doctrine about children of Mary, and you were right in rejecting the idea that any other offspring should come from the same virginal womb from which Christ was born according to the flesh. . . . For if they accept the doctrine on the authority of priests that Mary had a number of children, then they will strive with greater effort to destroy the truths of the faith.”
Perhaps the most persistent objection to Mary’s virginity postpartum is the frequent scriptural references to Jesus’ “brothers” (e.g., Matthew 13:55, Mark 3:31-35, Luke 8:20, John 2:12 and 7:3-5, Acts 1:14, Galatians 1:19 1 Corinthians 9:5). The most fundamental response is that the Greek word rendered “brother” in English (i.e., adelphos) can be used to designate not only a blood brother, but it also can be used to denote varying and even remote degrees of relationship. “Adelphos” (i.e., “brother”), standing alone, is thus inconclusive on the point. Further examination of the biblical texts alone reveals that at least some of these purported “brothers” were not the children of Mary (e.g., a couple were elsewhere identified as children of Mary, the mother of Clopas, who was at the Cross with the Blessed Virgin Mary; compare Mt. 13:55 and Mk. 6:3 with Mt. 27:56, Mk. 15:40, and especially Jn. 19:25). Further, nowhere in Scripture is the Blessed Virgin Mary ever explicitly identified as the earthly mother of anyone other than Jesus. There is additional argument that the “brothers” appear to be older than Jesus, and there is ample scriptural support for the proposition that Mary had no children before Jesus (e.g., Matthew 1:18-25, Luke 1:26-38 and 2:7).
Another objection is the reference to Christ as being a “firstborn” son. St. Jerome convincingly responds that every only child is a firstborn child, and he further explains that the Jewish practice was to offer sacrifice upon the birth of a “firstborn,” without the necessity of waiting for subsequent children to be born. Scripture scholars recognize that prototokos (“firstborn”) is only a legal status and only means no prior child, and it is sometimes the equivalent of monogenes (“only-born”).
Similar analysis can be used to dispel the inference drawn from Matthew 1:18, 25 that Joseph and Mary had relations after the birth of Jesus. (In these passages, reference is made to the time “before [Joseph and Mary] lived together” and to Joseph and Mary’s not having relations “until she bore a son.”) These passages merely assert that up to a definite point in time the marriage was not consummated, but does not speak to the issue of consummation after Jesus’ birth. St. Jerome cites many scriptural passages to support this thesis, including Isaiah 46:4; Matthew 28:20; 1 Corinthians 15:23-26; Psalms 122:2; Psalms 118:123; Genesis 35:4; Deuteronomy 34:5-6; Genesis 8:7; 2 Samuel 6:23.
The fourth major objection is based on an inability to reconcile postpartum virginity with Mary and Joseph’s having a “true marriage.” Marriage involves unconditional self-donation that may be physically expressed, but not necessarily. One may possess a right without its exercise. Consent, not consummation, is “the indispensable element that ‘makes the marriage’” (Catechism, no. 1626). St. John Paul II made it clear in his apostolic letter Guardian of the Redeemer (no. 7) that Joseph and Mary had a true marriage.
The foregoing is taken from Leon Suprenant, “Always a Virgin,” as printed in Hahn and Suprenant, Catholic for a Reason II: Scripture and the Mystery of the Mother of God (Emmaus Road). For even more detailed information on the “brothers and sisters” of Christ, see http://www.cuf.org/2004/04/the-brothers-and-sisters-of-jesus/.