When the Bible says that Mary brought forth her first-born son, doesn that mean that later she had other children too?
No, the term “firstborn” is a specialized legal term in Jewish liturgical law. It does not imply that there were other children. Recently, a significant number of tombstones from interestrumental times have been uncovered which tell of women who died in childbirth giving birth to their “firstborn” sons. They obviously had no other children.