Reformed Baptists affirm the virgin birth of Jesus Christ as a historical fact essential to Christian doctrine, as taught in the 1689 London Baptist Confession, Chapter 8. Jesus was supernaturally conceived in the womb of Mary by the Holy Spirit, without a human father. This virgin conception underscores the sinlessness of Christ's humanity and affirms the reality of the incarnation — God becoming human while remaining God.

The virgin birth is not presented merely as a sign or symbol but as an actual historical event recorded in the Gospel accounts of Matthew and Luke. The supernatural manner of Christ's conception is consistent with the divine nature of his person: only one born supernaturally could be the God-man mediator. The virgin birth protects Christ from the inherited corruption of original sin through natural generation.

Reformed Baptists, following Protestant orthodoxy, reject the doctrine of Mary's perpetual virginity. Scripture indicates that Mary bore other children after Jesus' birth (the "brethren of the Lord" in Matthew 13:55-56 and other passages). Mary is honored as the mother of Jesus but is not exalted as a mediator, intercessor, or perpetual virgin. She herself needed a Savior, having been born in sin like all humans except Christ.