Did Jesus Have Siblings?

Luke 2:7: Describes how Mary gave birth to her FIRST BORN SON. 

Protestant Christian Understanding:  This is proof that Mary had more children after Jesus.  Thus, suggesting again that she had relations with Joseph.

Catholic Christian Understanding: Mary only birthed one child and it was Jesus.  Again, we have to study what the Bible means when it uses the word "first born."  It simply means the first child you have as a parent, not referring at all to whether any others come afterward or not. Let's go back to Exodus 12 and 13 where the Jews had to offer up the first born child to God as his property and likewise with every animal.  When they did this, God did not turn them away and say no you cannot come into the tabernacle and offer your child to me until you have more kids to make this one the "true first born".  The "first born" terminology is a reference to the actual first born child of any parent, with nothing to do with whether or not any more kids were born after.  

Even in a Protestant lexicon when it comes to the Greek language, the term "PROTOTOKOS" is used in the bible which means first born son.  Bauer, Danker, Artndt and Gingrich is the Protestant book I found that uses this exact terminology in the same context.  The book gives an example of a grave found in Jerusalem where it says, "here lies the mother who died giving birth to her first born."  This also shows this term being used in this context that the child was the first born.  Nothing to do with any children after, because the lady is now dead and she only gave birth to one child, her first born or PROTOTOKOS.

Matthew 15 55:56 - Siblings of Jesus and did Jesus have actual brothers and sisters which Mary gave birth to.

Protestant Christian Understanding:  This is proof that Mary had more children after Jesus.  That Jesus was referring to his actual siblings, and the passage names them.

Catholic Christian Understanding:  Again we have a misunderstanding of terminology and the way the bible uses the word, "Brother".  Let's first go to the book of Geniuses to Chapter 13 where Abraham is speaking to Lott.  Abraham is Lott's uncle, and Abraham addresses Lott saying, "We are brothers" using the Greek word "Adelphoi", which is the exact same word Matthew uses in 15 55:56.  The word "Adelphoi" is the same word used in both passages,  Geniuses Chapter 13 and Matthew 15 55:56 and we have to stay consistent to draw a logical meaning.  This word does not mean that two people have the same mom and dad.  It can equally mean, or rather mean, that the two people are cousins or related, which is all it means in Matthew 13.  More proof of this can be found when we fast forward about 14 chapters to Matthew 27 55:56 when it is describing Jesus's death on the cross and the people that were present.  It describes a Mary, the mother of James and Joseph and it says, "Many women were there, watching from a distance. They had followed Jesus from Galilee to care for his needs. 56 Among them were Mary Magdalene, Mary the mother of James and Joseph, and the mother of Zebedee’s sons."  

The confusion is about the "Mary" described in this passage which is used to say that Mary the mother of Jesus, is being referenced here as the mother of two other, James and Joseph.  The Mary described as the mother of James and Joseph is clearly a different Mary and not the Blessed Virgin Mary, mother of Jesus.  It would make no sense for the scripture to describe her as the mother of James and Joseph when in fact her own Son is dying on the cross in front of her.  That is illogical.  The Mary being described here is not Mary the mother of Jesus, but in fact, there were three Marys present at the cross - Mary the Mother of Jesus, Mary Magellan, and Mary the mother of James and Joseph.  The third Mary identified as the mother of James and Joseph is a close kinswoman of Mary the mother of Jesus. John identifies her as the "sister" of Mary the mother of Jesus, but that still does not mean that they are sisters from the same parents anymore than it means they are sisters as cousins.  The history about Mary the mother of Jesus is that she is an only child.  No one named their children the same name, which both Mary's would have been named if they were truly sisters.  That never happened in any story in the bible.  

Furthermore, in John 19 when Christ is hanging on the cross and gives his mother Mary to mankind (John the Apostle) John explains that Mary, the mother of James and Joseph, is the wife of Clopas and is the sister of Mary the mother of Jesus.   

So in summary the "brothers" of Christ as referred to in all of these verses are not his actual brothers and sisters who the Blessed Virgin Mary gave birth to, rather they were related as cousins and not siblings.