There is not a single passage that teaches that Jesus "came down to Earth", on the contrary, Paul clearly stated, "....concerning God's son, Yeshua the Messiah, our Master, the one who comes from the [patrilineal] seed of David according to the flesh and the one who was designated son of God in power according to the spirit of Holiness by reason of a resurrection from the dead...." [Romans 1.1-4]
The early Greek fathers, who adopted the virginal conception idea from their Pagan beliefs, proposed that God impregnated a man's wife behind his back, and when he found out about it, told him that he was to put up with it. This is a character alien to God and insulting to Him.
On the other hand there were many Greek mythological heroes that had virgin births, even Plato:
"It is said, even when he was still alive, that Plato was of divine birth. The story, no doubt developed much after Plato's death, goes that the figure of god Apollo came to Plato's
virgin mother, Perictione, and
impregnated her. When his father, Ariston, attempted to lie with her, the god appeared to him in a vision, commanding him to
abstain from her for ten months
until the child was born.
...
By a frugal life and strict personal care, Plato lived to a great age. He died willfully on his own birthday, being exactly 81 years of age. The number 81 is holy. It is the called the "squared-squared number", and is the square of the number of Muses, the choir of his god Apollo.
On this Seneca wrote, "You know, I am sure, that Plato had the good fortune, thanks to his careful living, to die on his birthday, after exactly completing his eighty-first year. For this reason
wise men of the East, who happened to be in Athens at that time,
sacrificed to him after his death, believing that his length of days was too full for a mortal man, since he had rounded out the perfect number of nine times nine. I do not doubt that he would have been quite willing to forgo a few days from this total, as well as the sacrifice."
http://www.platonic-....org/plato.html
Interestingly, the Hebrew version of Matthew used by the Ebionites (who were the Jews that escaped from Jerusalem and were led by Jesus' brothers) lacked the birth narrative...