Was James the brother of Jesus born of another woman before the birth of Jesus?

The Bible never speaks of James as a half-brother of Jesus, only as his brother. In fact, the gospels talk of the relationship of Mary to James, Jude and their sisters as if they were her own children. This is particularly relevant: if they were Jesus' half-brothers and sisters, they would probably be a good deal older than Jesus, but if they were his full brothers and sisters they would be younger. The evidence of the Gospels of Matthew and Luke is that Jesus was born during the reign of King Herod, and Matthew appears to suggest that he was born some years before the death of Herod. Thus Jesus was born before April 4 BCE, when Herod died, and probably some years earlier.

James seems to be the oldest of Jesus' brothers and sisters, so if he was a half-brother, he would have been quite a few years older, but as a full brother he would have been born shortly after Jesus.

We have two accounts of the birth of Jesus. In Luke's Gospel, Mary and Joseph travelled from Nazareth to Bethlehem, but there is no mention of James or Jude accompanying them, an unlikely omission. In Matthew's Gospel, Mary and Joseph had their home in Bethlehem, but did later travel from Bethlehem to Egypt, with no mention of James or Jude accompanying them, once again an unlikely omission. On the evidence of the gospel accounts, it is likely that James was younger than Jesus.

Paul mentioned meeting James, the brother of Jesus, in Jerusalem perhaps as late as the 50s of the first century CE, and his description of James as a vigorous and alert leader makes him unlikely to have been an old man in his sixties or seventies. This also militates against James being older than Jesus.

The gospels do not tell us when James was born, but it was probably after the birth of Jesus. In Luke's Gospel he would have been born in Nazareth, probably before the year 1 CE. There is no mention in Matthew's Gospel of James accompanying the young family on the return from Egypt, although this can not be ruled out. In Matthew, James was likely more born in Nazareth some time after 3 BCE.