Don't Catholics believe Mary was without sin and go so far as it say she never had sexual relations with Joseph, even after the birth of Jesus? Which I feel is ridiculous seeing how the Bible says the marriage bed is undefiled. They also say his brothers were actually cousins to make their case.
I have known lots of Catholics who are true believers, but I disagree with this interpretation.
Yes, I do think many Catholics believe that Mary was without sin.
This is a conflation of two different ideas:
1) Mary is immaculate
2) Mary's perpetual virginity
The Immaculate Conception of Mary:
Disclaimer: I disagree with the Catholic position, but it's important be clear about what the Catholic position is.
In Catholic theology Mary was, on account of Christ and by the grace of God, conceived and born without the stain of Original Sin. This is the "Immaculate Conception"; in Catholic theology by virtue of Christ's atoning work God, by a special gift, ensured that Mary would be a pure vessel for the Son of God. She wasn't immaculate by her own virtue or merit, but by the virtue and merit of Jesus; that is Christ's work was retroactive in freeing His mother, and granting her an immaculate conception and birth so that she could be pure in her being His mother. The rationale for this is that in order for Christ to be conceived without sin, His mother had to have been set free from Original Sin.
The Catholic position is not that Mary was, by her own virtue, immaculate; but was by virtue of her Son immaculate, and this not for herself, but in order that she could be the pure vessel through which the Son of God was conceived. The point is ultimately to argue for how Mary could be the pure habitation for God Incarnate. It's not to say that Mary didn't need a Savior, she did, she was saved by her Son; but in a special case, by a special grace of God, by virtue of Christ and what Christ accomplished Mary was able to be pure for the purpose of conceiving and giving birth to Christ.
My personal argument against this is as follows: There is no need to make Mary pure in order for her Son to be conceived without the taint of sin; if by special grace Mary can be free from the taint of Original Sin by virtue of her Son, then how much more can Christ be born without the taint of sin by virtue of Himself? It just seems largely superfluous and unnecessary.
The Perpetual Virginity of Mary:
My own opinion here is that it's honestly just not my business to know the sex life of the mother of God. Whether she remained a perpetual virgin or not is irrelevant.
Tradition says that Mary remained a virgin even after giving birth to our Lord, that she and Joseph never consummated their marriage. This may seem strange at first, but also according to tradition Joseph was pretty old and a widower, and the marriage between Joseph and Mary was largely a legal matter.
It is important to remember that marriages in the first century would have largely been arranged marriages. We aren't talking about two people falling in love, then proposing, then getting married out of romantic love (not that people didn't fall in love, it's just that this wasn't really how marriage worked back then). It's not hard to conceive that there may be a case where a marriage was arranged in which a young woman was betrothed to an older man for him to be her guardian, effectively a legal protector in a society in which women had little to no power; and in which women were by and large regarded as the property of their fathers, and then later husbands.
As such, at least according to tradition, this was largely the kind of relationship Joseph and Mary had, and so they never engaged in conjugal activity even after Mary gave birth to Jesus.
The siblings of Jesus, then, were the children of Joseph from a previous marriage. Some later ecclesiastics, such as St. Jerome, toyed around with the idea that they may have been cousins, based on some ambiguity of the Greek word for "brother" which can, in some contexts, refer to close kin in general, and not sibling specifically.
In the end it really doesn't matter, but this is the very ancient opinion of the Church; and since Scripture is entirely silent on the matter, there's no reason to have a problem with it biblically. There's insufficient evidence to argue either case, and so there should be room for both opinions in Christianity.
-CryptoLutheran
