@Investigator,
Luke, like his companion Saul, who was later named Paul, never knew the living man Jesus and wrote his Gospel according to the stories told by others who had known the man Jesus.
Mark who is believed to be the son of Peter, and John the beloved disciple and nephew of Jesus, being one of the two sons of Salome, one of the sisters of Jesus who had married Zebedee.
And Matthew who knew that Mary was pregnant, before Joseph ben Jacob consummated his union with her, only after she had given birth to her firstborn son Jesus, the biological son of her half-brother Joseph ben Heli AKA Alexander Helios, who was the father of both Mary and her half-brother Joseph by different mothers.
And it was Matthew who said; “Now all this happened to make come true the words of the prophet (Isaiah) ‘An unmarried woman will conceive and bear a son and he shall be called Immanuel, which means God (Who filled the man Jesus with his spirit on the day of his baptism) is with us. For everyone who has ever seriously studied the scriptures knows that Isaiah never did say that a virgin would conceive, etc.