The difference between Protestants and Catholics here all starts with the Catholic view that Mary died a virgin. This is despite the plain talk in Matthew's gospel:-
And he knew her not till she brought forth her firstborn son: and he called his name JESUS (Matthew 1:25, Douay-Rheims Bible);
or in plainer English "But he did not have sexual relations with her until her son was born. And Joseph named him Jesus" (New Living Translation).
Some scriptures talk of Jesus's brothers, such as Matthew 12:46-50, Matthew 13:55-57, and Mark 6:3.
One RC opinion: "brothers" means "cousins"
So some Catholics say that brothers here means cousins. Protestants reply that there is a specific Greek word for cousins ("anepsios", see Colossians 4:10 - "cousin of Barnabas") which would have been more appropriate to use. Furthermore these brothers are always mentioned alongside Mary, but the supposed mother if they were cousins is never mentioned:
While Jesus was still talking to the crowd, his mother and brothers ("adelphio") stood outside, wanting to speak to him. Someone told him, “Your mother and brothers are standing outside, wanting to speak to you.” He replied to him, “Who is my mother, and who are my brothers?” 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, NIV).
And when the people of Nazareth do not believe on him they speak of Mary, his brothers (adelphio) and sisters being with them all. And Jesus replies "a prophet is not without honour except in his own country and in his own house" (Matt 13:57). These brothers and sisters who did not believe in him lived in the same house as him.
Second RC opinion - sons and daughters of Joseph by a previous marriage
Some Catholics agree with Protestants and say Jesus had real brothers. But then they say Mary could not have been their mother because she died a virgin. Therefore they must be half-brothers and Joseph had been married before and had children by a previous marriage.
Seeing these supposed children were by a previous marriage they would have been older than Jesus, who was 12 at the time he remained in the Temple. They would then have been suitable to help in the search for Jesus.
But the subsequent children of Mary which Protestants believe in would have been younger than Jesus and entirely unsuitable to help in the search for Jesus.
The problem of Luke 2:48 exists, then, not for Protestants but for those Catholics who believe Jesus had elder brothers by a previous marriage of Joseph. Those brothers would have been old enough to help in the search: seeing they are not mentioned as helping, Catholics who agree that Mark 6:3 and Matthew 12:47 refer to real half-brothers of Jesus and not cousins have a bit of a problem: they should have been mentioned in Luke 2:48. Protestants, on the other hand, have no problem at all, because the younger brothers and sisters are too young to help in the search, so they are obviously not mentioned as helping in the search.
There is a problem with the view that Mark 6:3 and Matthew 12:47 are speaking of older sons of Joseph by a previous marriage: Joseph was the direct descendant of King David; if the royal house of David still ruled Israel, Joseph, upon the death of his father, would have been the King of Israel. His oldest son was also the direct descendant of King David. Jesus simply must have been Joseph's oldest son (by adoption), else he would not have been the King of Israel upon the death of Joseph. In truth Jesus was not only spiritually the King of Israel but also literally/in the purely earthly sense the King of Israel. (So this option, I think, is really quite disastrous theologically. The "cousins" option at least doesn't produce this terrible consequence.)
There are two problems with the view that "brothers" simply meant "cousins":
- Galatians 1:19 speaks of James as being the Lord's brother.
"But other of the apostles I saw none, saving James the brother of the Lord." (Galatians 1:19, Douay-Rheims Bible)
It is really hard to imagine that what Paul meant was that James was the Lord's cousin, when there is a better word for "cousin" in the Greek. And
- The James' Ossuary has written on the side "James, son of Joseph, brother of Jesus". For reasons which are too detailed to go into here, I believe that ossuary is genuinely the ossuary of the brother of Jesus Christ our Lord. And it is impossible that "brother" on the side of an ossuary would mean "cousin".
Sorry to have to tell you this, but there is no Biblical evidence for the belief that Mary remained a perpetual virgin; there is evidence that she did not, both Biblical and extra Biblical.
The insistence that Mary remained a virgin her entire life is undoubtedly rooted in the unscriptural conception that celibacy is spiritually superior to marriage and child bearing. In both the Old and New Testaments, the Bible speaks of marriage as an honorable institution that was intended by God to be the norm for humanity from the very beginning of the Creation (Genesis 2:24; Proverbs 5:18-19; Matthew 19:4-6; 1 Corinthians 7:2-5; Hebrews 13:4). Mary’s marriage to Joseph, and their subsequent production of offspring after the birth of Jesus, had the approval and blessing of heaven. (https://apologeticspress.org/did-jesus-have-fleshly-half-brothers-1271/ )
Nevertheless, because of sexual immorality, let each man have his own wife, and let each woman have her own husband. Let the husband render to his wife the affection due her, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does. And likewise the husband does not have authority over his own body, but the wife does. Do not deprive one another except with consent for a time, that you may give yourselves to fasting and prayer; and come together again so that Satan does not tempt you because of your lack of self-control. (1 Corinthians 7:2-5).
Finally, even in the case of brothers and sisters who reject our witness for Christ we can take comfort that “We do not have a High Priest who cannot sympathize with our weaknesses but was in all points tempted as we are, yet without sin” (Hebrews 4:15). We might conclude, Jesus had to have brothers and sisters who did not believe on him so he could sympathize with us.