He had no earthly father; He abhorred to have one.  The thought may not be suffered that He should have been the son of shame and guilt.  He came by a new and living way; not, indeed, formed out of the ground, as Adam was at the first, lest He should miss the participation of our nature, but selecting and purifying unto Himself a tabernacle out of that which existed.  As in the beginning, woman was formed out of man by Almighty power, so now, by a like mystery, but a reverse order, the new Adam was fashioned from the woman.  He was, as had been foretold, the immaculate "seed of the woman," deriving His manhood from the substance of the Virgin Mary; as it is expressed in the articles of the Creed, "conceived by the Holy Ghost, born of the Virgin Mary."

Thus the Son of God became the Son of Man; mortal, but not a sinner; heir of our infirmities, not of our guiltiness; the offspring of the old race, yet "the beginning of the" new "creation of God.” ....

Thus did the Son of God enter this mortal world; and when He had reached man's estate, He began His ministry, preached the Gospel, chose His Apostles, suffered on the cross, died, and was buried, rose again and ascended on high, there to reign till the day when He comes again to judge the world.  This is the All-gracious Mystery of the Incarnation, good to look into, good to adore.

-- From a sermon by St. John Henry Newman on John 1:14