Summary: Jesus was born of a Virgin.
The Miracle of the Virgin birth
“And the angel answered and said to her, "The Holy Spirit will come upon you, and the power of the Most High will overshadow you; and for that reason the holy offspring shall be called the Son of God.”
A ten-year old, who was becoming quite knowledgeable about the Bible because of her grandmother’s teaching, asked her grandmother: "Which Virgin was the mother of Jesus? The Virgin Mary or the King James Virgin?" (Fresh Illustrations, http://www.freshministry.org/illustrations.html)
The belief in the Virgin birth is foundational in the Christian faith. It was predicted in Isaiah 7:13-14, which says, “ Then he said, ‘Listen now, O house of David! Is it too slight a thing for you to try the patience of men, that you will try the patience of my God as well?  "Therefore the Lord Himself will give you a sign: Behold, a virgin will be with child and bear a son, and she will call His name Immanuel.’”
Both Matthew and Luke record the Virgin Birth. Christian tradition supports it and it is incorporated in the Apostles’ Creed. Most Baptists aren’t familiar with the creeds of the faith, because we affirm that only the Bible is authoritative. So let me give you some background on the Apostle’s Creed.
It is the most popular creed used in worship by Western Christians. Its central doctrines are those of the Trinity and God the Creator. “Legend has it that the Apostles wrote this creed on the tenth day after Christ’s ascension into heaven . . . each of the doctrines found in the creed can be traced to statements current in the apostolic period.”
“The creed was apparently used as a summary of Christian doctrine for baptismal candidates in the churches of Rome, and, thus, became known as The Roman Symbol.” (Ages software commentary)
Here is the Traditional English Version of the creed: “I believe in God the Father Almighty, Maker of heaven and earth, And in Jesus Christ his only Son our Lord; who was conceived by the Holy Ghost, born of the Virgin Mary, suffered under Pontius Pilate, was crucified, dead, and buried; he descended into hell; the third day he rose again from the dead; he ascended into heaven, and sitteth on the right hand of God the Father Almighty; from thence he shall come to judge the quick and the dead.”
Notice the prominence given to the virgin birth in this creed.
Most Christians believe the Virgin Birth is true. According to George Barna, 85% of those surveyed believe that Jesus Christ was born to a virgin. He also found that even 75% of the people who do not embrace Jesus as their Savior believe that he was born to a virgin. (Fresh Illustrations, http://www.freshministry.org/illustrations.html)
In a day when many people quickly dismiss the miraculous, that’s a significant number of people who believe in this miracle. It is an amazing miracle isn’t it? I mean, how could a virgin give birth?
Actually, this was only one of two significant birth miracles in Mary’s family. When the angel appeared to Mary to tell her about the virgin birth, he told her about another miraculous birth. Her Aunt Elisabeth was pregnant too. Let’s read, Luke 1:34-37: “And Mary said to the angel, ‘How can this be, since I am a virgin?’  And the angel answered and said to her, ‘The Holy Spirit will come upon you, and the power of the Most High will overshadow you; and for that reason the holy offspring shall be called the Son of God.  And behold, even your relative Elizabeth has also conceived a son in her old age; and she who was called barren is now in her sixth month.  For nothing will be impossible with God.’"
The doctrine of the virgin birth is precious to believers because it establishes the Divinity of Jesus. The fact that Jesus was born of Mary, shows his Humanity. Most people agree that Jesus was fully human. According to Barna, 82% of those surveyed believe that when Jesus was on earth He was as much a human being as they are. (Fresh Illustrations, http://www.freshministry.org/illustrations.html)
But Jesus is fully divine too. The fact Mary was a Virgin when she gave birth, shows Jesus’ divinity. Because Mary was a virgin, it was medically impossible for Jesus to have an earthly father. The only acceptable explanation for this birth is the one Dr. Luke reported in Luke 1:35: “The angel spoke to Mary: ‘The Holy Spirit shall come upon thee, and the power of the Highest shall overshadow thee; therefore also that holy thing which shall be born of thee shall be called the Son of God’”
John did not write about the virgin birth. In fact, he did not write a Christmas narrative at all, instead, he began his gospel in eternity. He wrote: “In the beginning the Word already existed. He was with God, and he was God.  He was in the beginning with God.  He created everything there is. Nothing exists that he didn’t make.  Life itself was in him, and this life gives light to everyone.” (John 1:1-4 NLT)