Actually you can point to this passage from Matthew 13:55-56 to show this.
"Is not this the carpenter's son? Is not His mother called Mary, and His brothers, James and Joseph and Simon and Judas? And His sisters, are they not all with us? Where then did this man get all these things?"
We can also point to Paul who recognized James as the brother of Jesus.
Much to chagrin of the catholic, when read in context the Bible shows that Joseph and Mary had other children.
As explained in the Catholic Answers tract Brethren of the Lord, neither the Gospel accounts nor the early Christians attest to the notion that Mary bore other children besides Jesus. The faithful knew, through the witness of Scripture and Tradition, that Jesus was Mary’s only child and that she remained a lifelong virgin.
An important historical document which supports the teaching of Mary’s perpetual virginity is the Protoevangelium of James, which was written probably less than sixty years after the conclusion of Mary’s earthly life (around A.D. 120), when memories of her life were still vivid in the minds of many.
The Protoevangelium of James was so important to catholics that they didn't include it in the canon....not even when they had multiple chances.
Why?
The early Christian church recognized it for what it was....
The first mention of it is by Origen of Alexandria in the early 3rd century, who says the text, like that of a Gospel of Peter, was of dubious, recent appearance and shared with that book the claim that the "brethren of the Lord" were sons of Joseph by a former wife.[6]http://en.wikipedia.org/wiki/Gospel_of_James
So again, a catholic belief has been shown to be incorrect.....again.
BTW....Josephus knew Jesus had brothers and sisters.
And to so great a reputation among the people for righteousness did this James rise, that Flavius Josephus, who wrote the “Antiquities of the Jews” in twenty books, when wishing to exhibit the cause why the people suffered so great misfortunes that even the temple was razed to the ground, said, that these things happened to them in accordance with the wrath of God in consequence of the things which they had dared to do against James the brother of Jesus who is called Christ.
http://www.ccel.org/ccel/schaff/anf09.xvi.ii.iii.xvii.html
Man...it's embarrassing to have to keep correcting these selective quotes on this false roman catholic teaching.
you just don’t get it.
If you were the last person on this forum I wouldn’t give you the time of day.
go badger someone else.
AMDG
The first mention of it is by Origen of Alexandria in the early 3rd century, who says the text, like that of a Gospel of Peter, was of dubious, recent appearance and shared with that book the claim that the “brethren of the Lord” were sons of Joseph by a former wife.[6]http://en.wikipedia.org/wiki/Gospel_of_James
One has to be careful with Wikipedia to separate what the contributor writes from what is actually cited by the contributor. While it is true that the contributor wrote
that the text “was of dubious, recent appearance,” the citation does not show Origin questioning the authenticity of either gospel. Footnote [6] shows Origen writing “But some say, basing it on a tradition in the Gospel according to Peter, as it is entitled, or “The Book of James,” that the brethren of Jesus were sons of Joseph by a former wife, whom he married before Mary.”
http://en.wikipedia.org/w/index.php?title=Gospel_of_James&redirect=no#cite_note-Origen-6
Moreover, the very fact that the gospels are included in the apocrypha attests to their authenticity and that they are considered useful for instruction.
You can believe what you wish. I personally don’t think its worth arguing over. But there is no basis in stating that the belief is incorrect or that it is a false teaching. While the gospels do not rise to the level of absolute certainty about the perpetual virginity of Mary, neither is there evidence that proves the belief is incorrect. What the historical record clearly shows is that, as early as the mid-100’s, some early Christians believed that Mary was a virgin to the end.
Peace