"And Joseph also went up from Galilee, from the city of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and lineage of David, to be enrolled with Mary, his betrothed, who was with child." Luke 2.3

All the Gospels are emphatic that Jesus was fully man. The understanding of the human reproductive system in the ancient world considered the mother to be simply a vessel (like the soil in which the seed is planted) to contain and feed the child. It was the father alone who contributed all the human material that would develop into the future person. Without a human father, the Hebrew writers and Apostles would not have considered Jesus to have been fully human.
Matthew either misquoted Isaiah 7:14 in describing Mary as a "virgin" or it was changed later by Marianists when they were almost deifying Mary in the fourth century. Some Biblical scholars say as much both for the Matthew version and the verse where Mary expresses surprise at being told she will bear a son in Luke. Isaiah speaks of a "young woman" who shall conceive and bear a son. In the Greek translation of the Old Testament verse quoted, the word for "young woman" is ambiguous as it can mean either "young woman" or "virgin". The Hebrew is not ambiguous, there, it is definitely the word for "young woman." Matthew alone specifically mentions that "before they came together she was found to be with child." Luke, with his own unique version of the extraordinary birth of Jesus, does not quote or refer to the Isaiah passage at all. In Luke, the implication is that the Holy Spirit will play a part but he does not specifically rule out Joseph being the father. Neither Mark nor John (nor Paul’s letters for that matter) have any hint of the virgin birth story. It should also be noted that in Luke’s birth story, Mary’s surprise could well be surprise not at being told she will bear a child but at that child becoming the Messiah.

6, Mary was betrothed to Joseph. At that time in Jewish history betrothal was an official relationship; it often involved cohabitation culminating in legal recognition of marriage when the woman proved she was fertile. Most authorities agree that the virgin birth concept in Christianity did not become important until the fourth century. In Matthew the alteration of the text describing Mary as a "virgin" is fairly obvious; in the rest of his gospel, he does not mention the virgin birth again. Matthew is more concerned with defining Christ as "Emmanuel" – God present. Though not proof that Joseph is the genetic father of Jesus, there is a verse in John 6:42 where the Jews ask, "Is not this Jesus, the son of Joseph whose father and mother we know?"
7. Considering Roman Catholic teaching on Mary, Jesus’ own attitude to his mother in Mark (the earliest Gospel), is startling. There is the passage where Jesus is surrounded by a crowd and Mary and his brothers come and have word passed to the front that they want to speak to him. Jesus looks around at the throng and replies, "These are my mother and my brothers! For whoever does the will of God, the same is my brother, and my sister and my mother." Also in John, when Mary asks him to intervene in the situation where the host at a wedding feast had run out of wine, Jesus responds quite sharply, saying to Mary, "Woman what have I to do with you?" From the Gospels themselves it can be seen that Jesus’ development into the preacher of the Kingdom of God took place in very sharp opposition to his family, who were so little convinced of his mission that they held him to be insane (Mark 3:21). If Mary herself, was aware of the virgin birth, why then would she be unaware of his mission? And all the Gospels stress that Jesus separated himself from his family. It is only in Luke’s Acts that a member of Jesus’ family is mentioned as playing an important roll in the Church. James, the brother of Christ, is recorded in Acts 12:17 as being head of the Jerusalem Church.