[drone]

“The Virgin Birth It is a matter of Catholic faith that Mary was a Virgin at the conception and at the birth of Christ, and that she always remained a virgin after the birth of Christ.”
After Jesus was born Joseph did know his wife:
Matt 1:25 And knew her not till she had brought forth her firstborn son: and he called his name Jesus.

[Pete from Shawnee Mission]

Unfortunately the issue cannot be resolved on the basis of the English usage of "until." See:

http://biblehub.com/interlinear/matthew/1-25.htm

"καὶ ouk ἐγίνωσκεν αὐτὴν ἕως οὗ ἔτεκεν υἱόν;"

ἕως is the greek preposition "until."

And this from the "Greek Expositors Bible":

"ἕως does not settle the question. It is easy to cite instances of its use as fixing a limit up to which a specified event did not occur, when as a matter of fact it did not occur at all. E.g., Genesis 8:7; the raven returned not till the waters were dried up; in fact, never returned (Schanz)."

There are number of commentaries discussing the use of the word until and this question.

http://biblehub.com/commentaries/matthew/1-25.htm

Good studying!

[metmom]

And it says “her FIRSTBORN” son, not her ONLY son.

[Theophilus]

He knew her explicitly so to speak.

1 Corinthians 7:5
Defraud ye not one the other, except it be with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency.

Hebrews 13:4
Marriage is honourable in all, and the bed undefiled: but whoremongers and adulterers God will judge.

Galatians 1:19
But other of the apostles saw I none, save James the Lord's brother.

Thank the Lord that Mary did not defraud Joseph and for James the Lord's brother the offspring of their Holy Matrimony!