The Virgin Mary is the Theotokos, the mother of Jesus Christ, the Son and Word of God. She conceived by the power of the Holy Spirit. She was cared for by her betrothed husband, Joseph, who took the child and his mother into his home as his own. One very strong tradition in the Orthodox Church holds that the birth of Jesus was also miraculous and left Mary's virginity intact as a sign; it is also the tradition of the Church that Joseph and Mary did not have relations after the birth of Jesus.
Theotokos (in Greek, Θεοτοκος) is a Greek word that means "God-bearer" or "Birth-giver to God."
As a title for the Virgin Mary, Theotokos was recognized by the Orthodox Church at Third Ecumenical Council held at Ephesus in 431. It had already been in use for some time in the devotional and liturgical life of the Church. The theological significance of the title is to emphasize that Mary's son, Jesus, is fully God, as well as fully human, and that Jesus' two natures (divine and human) were united in a single Person of the Trinity.