Incarnation: The Person and Life of Christ, Thomas F. Torrance.
Here we have a verse, not recognized often enough, where explicit mention is made of the virgin birth of Jesus…If it is plural, there is a difficult connection in the Greek, but even so there is clearly an extended reference to the virgin birth—‘born not of bloods, nor of the will of the flesh, nor of a husband, but of God.’ The word translated in the KJV and RSV here as ‘man’ should be more accurately translated as ‘husband’—the Greek is not anthropou (man generically, male or female) but Andros (a male person, a husband). [cf. REB (REV), ‘born not of human stock, by the physical desire of a human father, but of God’; NIV, ‘born not of natural descent (Gk of bloods), nor of human decision or a husband’s will, but born of God’.]
All the main MSS give the plural reading except the Verona Old Latin (a MSS significantly of Ephesian origin) which gives the singular. These are all 5th century MSS. But there is considerable patristic evidence going back to the second and third centuries, Tertullian, Iraneau, Justin Martyr, Epistola Apostolorum, and Hippolytus, Clement of Alexandria—that is, all the available patristic evidence has John 1.13-14 in the singular at that date. Nowhere to my knowledge is there evidence at that date for the plural (unless it is in the gnostic documents not yet available to me). But evidence for the singular is also given by Ambrose and Augustine, and ambiguously by Leo the Great (who uses the plural as well as the singular), and many codices, such as 10, 14, 36, 37, etc. it is worth noting that most of these sources have at least a connection common with the Ephesian text…That is a most impressive weight of evidence for the singular reading, all twice as old as the oldest of our main codices…It must be in line with this too that the Johannine ‘only-begotten Son’ is to be understood, as well as the references in John 3 to being ‘born from above’ (anothen) which has primary objective reference to Christ himself. This was certainly the way in which Irenaeus understood it.
But now let us take a Johannine passage from the first epistle, ‘We know that any one born of God does not sin, but he who was born of God keeps him.’ [1Jn 5.18] Here John uses the perfect tense of the Christian, but the one spoken of in the aorist tense as ‘he who was born of God’ is certainly Christ himself, the one whom the fourth Gospel calls the only-begotten [monogenes], Jn 1.14, 18; 3.16 KJV] of the Father. It is upon Christ’s unique birth once and for all that our birth depends and in his birth that we are given to share. That again strengthens our understanding of the relation of John 3 (which speaks of being ‘born from above’ and of the who ‘descends from above’) to John 1 (the only-begotten, ‘who was born not of bloods, nor of the will of the flesh, nor of a husband but of God’).
Think of the significance of John 1.13 for the Johannine doctrine of baptism. Christ’s birth was the one unique event, and our birth in Christ is a participation in his birth. That is the very heart of Christian baptism. In Christian baptism we are born from above because in baptism we are incorporated into the one who was born of the Spirit from above, whose birth was marked by miracle as the new beginning for mankind. St Paul says, when Christ died, I died, and when Christ rose again, I rose again. St John teaches likewise, when Christ was born of the Spirit, I was born of the Spirit. Baptism thus reposes upon the virgin birth of Christ as well as upon his death and resurrection. Now that is precisely the way in which it is expounded by Irenaeus who uses John 1.13 in the singular, where, incidentally, he gives us the earliest doctrinal understanding of infant baptism. This relation of our baptism to the baptism of Christ, our new birth to Christ’s birth from above, was indeed the conviction of all the great fathers in the first five centuries, and even when the text in John 1.13 began to become plural (sometimes with a singular verb, and sometimes with a singular subject and a plural verb!). thus even in the works of Augustine and Leo the Great (where we find John 1.13 cited in both plural and singular forms), they nevertheless continued to expound baptism as our sharing in Christ’s virgin birth, and constantly cite this very passage in support. [Wolfgang Harnisch of Marburg cites P.L. Hofrichter, FZB 31, 1978, pp 155f; Das Urchristliche Logosbekenntnis, 1986.]