The Virgin birth of Jesus Christ is a miracle recorded in the Bible, revealing that Jesus was born of the Virgin Mary, having been conceived by the Holy Spirit and not by relations with any man. This belief has been a traditional tenet of Christianity and continues to be held by most Catholics and Protestants. However, this doctrine is not considered essential by many within liberal Christianity.
The Angel Gabriel went to Mary and said,
"Greetings, you who are highly favored! The Lord is with you. Do not be afraid, Mary, you have found favor with God. You will be with child and give birth to a son, and you are to give him the name Jesus. He will be great and will be called the Son of the Most High. The Lord God will give him the throne of his father David, and he will reign over the house of Jacob forever; his kingdom will never end."
"How will this be since I am a virgin?"
The Angel answered,
"The Holy Spirit will come upon you, and the power of the Most High will overshadow you. So the holy one to be born will be called the Son of God. Even Elizabeth your relative is going to have a child in her old age, and she who was said to be barren is in her sixth month. For nothing is impossible with God."
"I am the Lord's servant, may it be to me as you have said."
The doctrine was well established by the 2nd century, but theologians were always puzzled that Paul never mentioned it, though some commentators believe the wording of Galatians 4:4 alludes to the virgin birth.
Roman Catholicism also holds that Mary remained a virgin even after her marriage to Joseph, which doctrine most Evangelical [Protestants disagree with, because of the wording of Matthew 1:25 and the basic description of marriage (Mt. 19:4,5; 1 Cor. 7:2-5), the absence of any discussion of Mary's perpetual virginity in the canonical gospels, and references indicating Mary had children (i.e. plural). (Ps. 69:8; Mt. 12:46; 13:55; Jn. 2:12; 7:3,5,10; Acts 1:14; 1Cor. 9:5; Gal. 1:19)  Roman Catholic apologists believe these texts refer to close kin outside the immediate family, and otherwise dispute the Protestant conclusions. 
In some 21st century mainstream Protestant denominations, belief in the Virgin Mary is considered optional.
Many Protestants identify Catholics as worshippers of Mary. Catholics vigorously deny that they worship any being but God.
The Islamic Koran contains references to Jesus and Mary, but this much later work by Muhammad is critically different from the Bible. While Jesus is presented as a perfect man, and Mary is portrayed as an extraordinary mother of a great prophet, Muhammad denied the Divinity of Jesus, and that He was conceived from a virgin mother. In addition, he mistakenly understood that the Christian Trinity consisted of God, Jesus and Mary. (Sura 5:116-117)  None of the thousands of extant biblical manuscripts support the Islamic contradictions of the Bible, though it requires its support. For a more detailed treatment, see Qur'an.
- Mary F. Foskett, A Virgin Conceived: Mary and Classical Representations of Virginity (2001) excerpt and text search. looks at the many complex meanings of Virgin Birth in the first two centuries
- Robert Gromacki, The Virgin Birth: A Biblical Study of the Deity of Jesus Christ (2nd ed. 2002), Evangelical perspective. excerpt and text search
- Americans Express Their Views of the Virgin Birth of Christ Barna research, December 17, 2007
- Roger E. Olson, The Westminster handbook to evangelical theology, p. 281
- Robert Paul Lightner, Handbook of evangelical theology: a historical, Biblical, and contemporary, pp. 79,80
- Albert Barnes' Notes on the Bible; John Gill's Exposition of the Entire Bible; Jamieson, A. R. Fausset and David Brown; Robertson's word pictures in the New Testament
- International Standard Bible Encyclopedia, Mary
- Dwight Longenecker, David Gustafson, Mary: A Catholic Evangelical Debate, p. 93-78
- See for example Donald K. McKim, Presbyterian questions, Presbyterian answers: exploring Christian faith (2003) online pp. 31-2