I don't have the time to read the ennntiiirrre thread, but I did a word search and noted that none of my fellow Catholics seemed to cite the proof-text for the miraculous nature of Christ's birth "as light passing through glass."
Matthew 1:23 "Behold a virgin shall be with child, and bring forth a son, and they shall call his name Emmanuel, which being interpreted is, God with us."
Cf. Isaiah 7:14.
The noun "virgin" is the subject of both verbs.
Has anyone pointed out that by conceiving Christ within the womb of the Blessed Virgin, the Holy Spirit took on the role of "actual" spouse, while Saint Joseph adopted the role of "lawful" spouse in the eyes of men? Saint Joseph would therefore have honored and respected her as the spouse of the Holy Spirit.
I remember that the Association of Hebrew Catholics once had a newsletter article explaining how these roles of the Holy Spirit and Saint Joseph were covered in Jewish Law.
The Douay-Rheims Bible has a nice footnote regarding that "until" in Matthew 1:25.
http://www.drbo.org/chapter/47001.htm
"Till she brought forth her firstborn son"... From these words Helvidius and other heretics most impiously inferred that the blessed Virgin Mary had other children besides Christ; but St. Jerome shews, by divers examples, that this expression of the Evangelist was a manner of speaking usual among the Hebrews, to denote by the word until, only what is done, without any regard to the future. Thus it is said, Genesis 8. 6 and 7, that Noe sent forth a raven, which went forth, and did not return till the waters were dried up on the earth. That is, did not return any more. Also Isaias 46. 4, God says: I am till you grow old. Who dare infer that God should then cease to be: Also in the first book of Machabees 5. 54, And they went up to mount Sion with joy and gladness, and offered holocausts, because not one of them was slain till they had returned in peace. That is, not one was slain before or after they had returned. God saith to his divine Son: Sit on my right hand till I make thy enemies thy footstool. Shall he sit no longer after his enemies are subdued? Yea and for all eternity. St. Jerome also proves by Scripture examples, that an only begotten son, was also called firstborn, or first begotten: because according to the law, the firstborn males were to be consecrated to God; Sanctify unto me, saith the Lord, every firstborn that openeth the womb among the children of Israel, etc. Ex. 13. 2.
I should have added that the virgin bringing forth her child while remaining a virgin is just as much part of the miraculous sign given to King Achaz by Isaiah as the virgin conceiving.