Why was Jesus born of a Virgin instead of just being conceived of a Virgin?

I know the Bible teaches the virgin birth, but why did the Blessed Mother refrain from sex during her pregnancy with Jesus (9 month gestation period)? After all, she was married to St. Joseph.

Do any Catholic theologians deal with this topic?

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    The perpetual virginity of Mary is largely a Catholic doctrine. Most other Christian denominations reject it. And the Bible nowhere says that Mary refrained from sex even after the Incarnation. So if you're going to ask this question, you need to scope it to Catholicism, or at least to denominations that hold to the perpetual virginity of Mary (which, once again, mostly means the Catholic Church anyway). Also, the question in the title and the question in the body don't quite mach. What, exactly, are you asking? Commented Jan 25, 2018 at 18:05
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    @Lee Woofenden "the Bible nowhere says that Mary refrained from sex after the Incarnation" yes it does. Jesus came into this world, and for 9 months Blessed Mary refrained from sex. Every Christian denomination I know of believes that Jesus EXISTED before birth. The Incarnation is not birth but Conception. I'm asking why did Mary refrain from sex during the gestation period.
    – aska123
    Commented Jan 25, 2018 at 18:29
  • Humans have a gestation period of around 9 months and Jesus was not an exception.
    – aska123
    Commented Jan 25, 2018 at 18:32
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    The question still is unclear. If you mean to ask why she did not have sex between conception and birth, then please say that clearly in the question. Even if, as you say, the event of the Incarnation took place at conception rather than birth, "after the Incarnation" would still include all time after the Incarnation, not just up to the time of Jesus' birth. Commented Jan 26, 2018 at 4:00
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    @Kris The term "incarnation" is not used to describe the birth of Jesus, but his conception. The question is asking why the blessed mother refrained from sex in the 9 month gestation period.
    – aska123
    Commented Jan 26, 2018 at 15:55

2 Answers 2


An answer from catholic church teaching to satisfy your curiosity regarding

Why was Jesus born of a Virgin instead of just being conceived of a Virgin?

Short answer: she was conforming her will to God's. This short answer is supported by the following points that the Catechism of the Catholic Church does a decent job of explaining.

  • It is worth noting that she was fulfilling the prophesy in Isaiah Chapter 7, but that may not directly bear on your question:

    13 And he said, Hear ye now, O house of David; Is it a small thing for you to weary men, but will ye weary my God also? 14 Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.


CCC 484 The Annunciation to Mary inaugurates "the fullness of time", the time of the fulfilment of God's promises and preparations. Mary was invited to conceive him in whom the "whole fullness of deity" would dwell "bodily". The divine response to her question, "How can this be, since I know not man?", was given by the power of the Spirit: "The Holy Spirit will come upon you." { ~ As told in Luke, Chapter 1 ~ }

No carnal act was necessary for conception. Since she had not had (per scripture) carnal acts before conception, there's little reason to believe that she'd change her habits and begin to have carnal acts afterwards, particularly when she understands that she's about to become filled with the Holy Spirit1. From Luke 1:38

38 And Mary said, “Behold, I am the handmaid of the Lord; may it be done to me according to your word.”

I've seen some translations render that as "according to thy will."

What is God's will in this case?

Remembering that Catholic belief is Trinitarian, the Holy Spirit's acts align with God's will by default.

485 The mission of the Holy Spirit is always conjoined and ordered to that of the Son. The Holy Spirit, "the Lord, the giver of Life", is sent to sanctify the womb of the Virgin Mary and divinely fecundate it, causing her to conceive the eternal Son of the Father in a humanity drawn from her own.

So far, after conception and before birth, no sin touches the vessel that bears Christ up to the point of birth. Since Mary is aware that something very special is going on, and she has assented to God's will in this, it is unreasonable to conclude that she would start having sex once all of the above took place and she had conceived by the Holy Spirit. (That answers why the Blessed Mother refrained from sex even after the incarnation).

CCC 507 At once virgin and mother, Mary is the symbol and the most perfect realization of the Church: "the Church indeed. . . by receiving the word of God in faith becomes herself a mother. By preaching and Baptism she {the Church} brings forth sons, who are conceived by the Holy Spirit and born of God, to a new and immortal life.

The above is supported by theological teaching and scripture as follows:
Lumen Gentium 63; 1 Corinthians 7:34-35; St. Augustine, De Virginante. 3: PL 40, 398; Lumen Gentium 64; St. Thomas Aquinas, Summa Theologica III q. 28 a. 2; Luke Chapter 1.

Given her commitment to God's will in this, remaining virgin is both a matter of consistency, and a way that Mary fulfills her role as the model of faith and adherence to will of God that the Church is to follow.

1 Matthew 1: 24-25 shows Mary still being a virgin at the time of birth, and with the marriage not being consummated until afterwards.

  • Matthew 1: 24-25 would help show that scripture indicates Mary was still a virgin at the time of birth.
    – Kristopher
    Commented Jan 25, 2018 at 17:35
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    Re: Your footnote: My understanding is that according to Catholic doctrine Mary's marriage to Joseph was never consummated; that Mary remained a virgin throughout her entire life. I don't think this is biblical, but I do think it's the teaching of the Catholic Church. Commented Jan 25, 2018 at 18:54
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    I would suggest checking Catholic doctrine on this. My understanding is that the Catholic Church denies that the marriage was ever consummated, states that Mary never had sex, and states that Jesus' siblings mentioned in the Bible were not children of Mary. If I am wrong about this, I would be happy to be corrected, but I don't think I am wrong. Commented Jan 25, 2018 at 19:19
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    @Marc It seems that the change continues, and another related question has been asked. Commented Jan 29, 2018 at 15:24
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    @KorvinStarmast I don't think so. The idea that God couldn't make true statements about the world at a particular time that would not be true at a later time is patently false.
    – curiousdannii
    Commented Jan 29, 2018 at 15:27

Virgin during her pregnancy

She was a virgin during her pregnancy because prior to the Annunciation she took a vow of virginity:

Augustine says (De Sanct. Virg. iv):

Mary answered the announcing angel: "How shall this be done, because I know not* man?" [Lk. 1:34] She would not have said this unless she had already vowed her virginity to God.

*The Greek uses the present tense "ου γινώσκω" ("I do not know") and not the past "I have not known (up to this time)". The present tense shows that she has preserved her virginity and that she also intends to preserve it in the future; it indicates her permanent state of "not knowing man" (i.e., of not having sexual intercourse). See Mariology vol. 2, p. 236, by Carol B. Juniper, O.F.M.

Virgin during Jesus's birth

She was a virgin during Jesus's birth because

  1. this was in keeping with a property of Him whose Birth is in question, for He is the Word of God. For the word is not only conceived in the mind without corruption, but also proceeds from the mind without corruption. Wherefore in order to show that body to be the body of the very Word of God, it was fitting that it should be born of a virgin incorrupt. Whence in the sermon of the Council of Ephesus (quoted above) we read:

    Whosoever brings forth mere flesh, ceases to be a virgin. But since she gave birth to the Word made flesh, God safeguarded her virginity so as to manifest His Word, by which Word He thus manifested Himself: for neither does our word, when brought forth, corrupt the mind; nor does God, the substantial Word, deigning to be born, destroy virginity.

  2. this is fitting as regards the effect of Christ's Incarnation: since He came for this purpose, that He might take away our corruption. Wherefore it is unfitting that in His Birth He should corrupt His Mother's virginity. Thus Augustine says in a sermon on the Nativity of Our Lord: "It was not right that He who came to heal corruption, should by His advent violate integrity."

  3. it was fitting that He Who commanded us to honor our father and mother should not in His Birth lessen the honor due to His Mother.

—St. Thomas Aquinas, Summa Theologica III q. 28 a. 2 ("Whether Christ's Mother was a virgin in His birth?") c.

It is worth noting that the Council of Ephesus was in 431, so this represents an agreed belief of the early Church.

  • 1
    To the downvoter: why the downvote?
    – Geremia
    Commented Jan 26, 2018 at 16:53
  • No idea about a down vote, but your answer really addresses only the part of the dogma idea of ever-virgin that Mary remained a virgin even in the act of birth. It doesn't address the actual OP question about why she remained a virgin after the incarnation (birth of Christ). Don't worry, however, most fail to understand the fine distinction of the ever-virgin dogma (before, during, after incarnation), but read the first sentence of your quote from Aquinas from the Council of Ephesus.
    – SLM
    Commented Jan 26, 2018 at 19:28
  • @SLM the question asks why Mary had no sex during pregnancy not after birth. OP believes incarnation refers to conception.
    – Kristopher
    Commented Jan 26, 2018 at 19:46
  • @Kris Thanks for the clarification. I've added a section on why she is a virgin during her pregnancy.
    – Geremia
    Commented Jan 26, 2018 at 20:02
  • I'm shocked at the amount of people that do not belive the Incarnation refferes to the Conception of Christ.
    – aska123
    Commented Jan 26, 2018 at 22:00

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