ANSWER: (1) Three of the four oldest manuscripts, two of the oldest versions, three ancient commentators, and the following critical editions: Tregelles, Weiss, and Westcott and Hort sustain this marginal reading. Several ancient writers quote it as written by John, and others use the expression "the only begotten God," without referring it to the Scriptures, just as we use many scriptural phrases, without saying they are quotations. We predict that the next revision will put this marginal reading in the text, and the present text in the margin. (2) We do not believe that either of these readings relate to the virgin birth. Adam Clarke and Moses Stuart believed that the Logos did not become the Son of God till he became the son of Mary. Richard Watson felt called to refute this error. His extended and unanswerable argument in proof of the "eternal Sonship of Christ" is found in his Institutes.
— Steele's Answers pp. 56, 57.