What biblical evidence is there that Mary did not go on to have further children after the virgin birth of Jesus?
The following links should help you understand the Church's position on whether Jesus had brothers. If you have any further questions, please contact Catholic Answers directly.
*] Doesn't Scripture imply that Mary had children other than Jesus?
*] Did Jesus have brothers?
*] Perpetual Virginity: Why is this important?
*] Mary: Ever Virgin