Matthew 1:25
And knew her not till she had brought forth her firstborn son: and he called his name JESUS. (KJV)
but had no marital relations with her until she had borne a son;[a] and he named him Jesus. (NRSV)
Footnotes:
Matthew 1:25 Other ancient authorities read her firstborn son
I think the latter is a proper Catholic translation. The footnote applies to it.
Matthew 1:25, when he writes that Joseph “knew not” (i.e., was not sexually intimate with; cf. Gen. 4:1) Mary “UNTIK [Greek: heos hou] she had given birth to a son”, what is the plain meaning?
While the Greek expression heos hou does not absolutely demand that Joseph and Mary were intimate after Jesus’ birth, that would be the normal conclusion, unless contextual considerations indicated otherwise (see for instance, 2 Sam. 6:23).
In fact, elsewhere in the New Testament (see Matthew 17:9 24:39; and John 9:18) the phrase (heos hou) followed by a negative always implies that the negated action did take place later” .
There is no valid reason, for me, why Matthew 1:25 should be the exception.
Also, In Luke 2:7, Jesus is called Mary’s “firstborn” (prototokon) child.
While the term prototokon does not demand unequivocally that Mary had other children, this term “most naturally suggests” that she did.
Now If the perpetual virginity of Mary is such a crucial theological point, why did not Luke simply say that she brought forth her “only” son?
That certainly would have settled the issue.