Because of the doctrine of Biblical inerrancy, a book could be rejected if one thing and one thing only was wrong with it. Or, it could simply be rejected because, though orthodox and pious, it had no claim to Apostolic authority.
That doesn’t mean everything in the book is automatically disqualified along with it.
If I wrote a purported book of the Bible, nobody would accept it—for good reason. But if I claimed in the book that Christ died on a cross and was raised from the dead, that would still be true wouldn’t it?
If the facts can be verified.
However, the passage in Luke 1:34 where catholicism claims Mary makes a perpetual vow of virginity is not supported by the Greek. There was another thread on this where I posted the breakdown of the Greek in response to the original poster. The thread title is:
A scriptural defense of the Perpetual virginity of Mary
My post is #69 if you want to read it.
The OP also posted another challenge regarding if anyone could find an Early Church Father from the first 300 yrs or so that denied the Perpetual Virginity.
My reply is post 102 in the same thread.