Top 10 Ways that Mel's Passion Isn't As It Was, Number 9...

9. Mary the mother of Jesus had other sons.

Mr. Gibson is a Catholic schismatic who has rejected the Vatican II Council. He has privately funded the construction of a church in the Our Lady of Malibu diocese, calling it the Church of the Holy Family of Malibu.

Not that there's anything wrong with that. But this adherence to what Mr. Gibson sees as traditional Catholic doctrines makes this next deduction about the movie a piece of cake.

He will portray Mary as having no other child but Jesus.

In Catholic doctrine, Mary remains a virgin all of her life. This was declared so in 553 CE, at the 5th Ecumenical Council. It was considered abhorrent that the same womb which nurtured Jesus could have produced other children. Mary's womb becomes the Christian Most Holy Place, and no mortal seed can be allowed to gain purchase there.

It doesn't matter that the Christian scriptures talk about a group of men being Jesus's brothers:

While he was still speaking to the crowds, his mother and his brothers were standing outside, wanting to speak to him. Someone told him, "Look, your mother and your brothers are standing outside, wanting to speak with you." But to the one who told him this, Jesus replied, "Who is my mother, and who are my brothers?" And pointing to his disciples, he said, "Here are my mother and my brothers! For whoever does the will of my Father in heaven is my brother and sister and mother."

Matthew 12: 46-50, NRSV
It doesn't matter that the scriptures even list the names of four:
"Is this not the carpenter's son? Is not his mother called Mary? And are not his brothers James and Joseph and Simon and Judas? And are not all his sisters with us?"

Matthew 13: 55-56, NRSV
It doesn't even matter that one of these brothers is mentioned by a historian who lived during this time period:
Festus was now dead, and Albinus was but upon the road; so [Ananus] assembled the sanhedrim of judges, and brought before them the brother of Jesus, who was called Christ, whose name was James, and some others; and when he had formed an accusation against them as breakers of the law, he delivered them to be stoned.

Josephus, Antiquities 20.9.1
No, Mary is a perpetual virgin because the Church said so. This is the logic of creation science, or of the church scholars who opposed Galileo. And Mr. Gibson will be honoring this doctrine, not the clear evidence to the contrary both in and out of the Christian scriptures. It makes for a great story, and a daunting doctrine - but history it's not.