Did Mary have other children?
Yes, Not all believe the Bibles record. Roman Catholics do not because of their tradition that is not from the Bible.
Here is what is specifically written.
In Mt. 13:55 and Mk.6:2-3 it says, “is this not the carpenter, the son of
Mary and the Brother of James, Joses, Judas, and Simon.”
Mt.13:56 adds, “and his sisters, are not they all with us?”
In Jn.7:3: “his brothers therefore said to Him, depart from here and go into Judea that your followers might see the works you are doing.” In vs.5: “ for even His brothers did not believe him.”
This does not have the impact if they are only His cousins, however it doesmake sense if it is His own family that are in disbelief. Which is exactly the point of the Scripture saying “even His brothers did not believe him.” These same brothers that are mentioned in Mt.13:55 and Mk.6:2-3 are mentioned by name later in the epistles and Identified as his blood relationship to his mother.
The same ones who did not believe during his ministry became believers after
the resurrection. Gal.1:19 mentions James as the Lord's brother, by
Jude in verse one of his letter calls himself the brother of James. The same James Paul has spoken of and the same James and Jude mentioned in the family of Jesus in the gospels. The Bible interprets itself on this matter. This is not hidden but in the open.
John 2:12: “After this He went down to Capernaum, He, His mother, His brothers, and His disciples; and they did not stay there many days.”
Notice it makes a distinction between His brothers and disciples (which would
be brethren). Brothers is specific, as the intent is to show family as it
Luke 8:19-21 also records His mother and brothers coming to see Him but
cannot get near because of the crowd. He's told that they are outside wanting to
see him, and His response is “my mother and brothers are those who hear God's
For one to discount the setting of these records as being Mary’s children, they would also have to refuse that Mary was a mother, even to Jesus. In other words, if He didn’t have brothers or sisters, than by the same measure He didn’t have a mother.
Clearly this shows that Jesus had a family, and they did reject him at first (except Mary his mother).
Even God teaches Joseph and Mary had children after Jesus was miraculously born. Mt. 1:24-25 Then Joseph, being aroused from sleep, did as the angel of the Lord commanded him and took to him his wife and did not know her till she had brought forth her firstborn Son. And he called His name Jesus (and Luke 2:7)