Summary
Jesus' mother and brothers turn up looking for him.
Biological brothers
The first thing to note is that Jesus has brothers. There's no reason to be sure these are Jesus' full brothers, but conversely, there's no reason to be sure they're not either. I don't see anything wrong with the natural interpretation that they're probably children of Joseph and Mary.
The author of Mark certainly didn't go out of his way to disabuse the notion.
On the other hand, I don't see any theological problems with the idea that M+J had other children. They may be Jesus' younger brothers. Or even if Jesus' birth was a miracle, it might still have involved normal sexual reproduction, but God did something miraculous to provide the soul, and the virgin birth story was a later exaggeration to fit the old testament supposed-prophecies.
Jesus' mother and brothers turn up looking for him.
Biological brothers
The first thing to note is that Jesus has brothers. There's no reason to be sure these are Jesus' full brothers, but conversely, there's no reason to be sure they're not either. I don't see anything wrong with the natural interpretation that they're probably children of Joseph and Mary.
The author of Mark certainly didn't go out of his way to disabuse the notion.
On the other hand, I don't see any theological problems with the idea that M+J had other children. They may be Jesus' younger brothers. Or even if Jesus' birth was a miracle, it might still have involved normal sexual reproduction, but God did something miraculous to provide the soul, and the virgin birth story was a later exaggeration to fit the old testament supposed-prophecies.