Leaving aside the whole querstion of God... because it's not logical, and pagan.
If I believed in God, I would do it in the most naturalistic terms. the thought that God is a human personality is strange in itself. having a son seems like you model a divine family, a human household.
we might as well hang photos of Isis with the child Horus in our houses instead of Mary and baby Jesus.
simplification, perhaps. but the question itself does not elaborate.
also try to look at it in the historical sense. why would common Jews accept that one of their fellow neighbours, had a son which was in fact God's son.
if a baby was born in the Philippines today, and people claimed that he is the son of God, how would you feel about it?