Catholics believe that every human being is born sinful, this is called Original Sin. When we are baptised we accept and choose to live in a relationship with God and we are cleansed of Original Sin.
Catholics believe that in preparation for God's plans, for Mary to become Mother of Jesus, God allowed her to be conceived without sin. This would mean that Mary as Jesus' only human parent would not pass Original Sin onto her son.
Essentially the Immaculate Conception is the belief that Mary was fully graced by God (Luke 1:28) and was conceived without original sin. Making it possible for Jesus to be human like us in all every way, except in sin.
"O Mary conceived without sin, pray for us who have resource to you" (a Traditional Marian Prayer)
MARY, MOTHER OF GOD
The Church teaches us that Jesus was both fully human and fully divine and that both natures were equally present throughout Jesus' life on earth.
Because Jesus is truly God in human form, Mary must be the Mother of God too. This was expressed in the title, Theotokos which literally means 'God-bearer' or the one who carried God.
Essentially Mary, Mother of God is that belief that Mary is the mother of Jesus, and if Jesus is God, then Mary is the Mother of God. We also believe that Mary is the Mother of God because of who Jesus truly is.
"This is how the birth of Jesus Christ came about: His mother Mary... was found to be with child through the Holy Spirit." (Matthew 1:18)
IN THE WAY OF MARY
Mary was the first disciple of Jesus. She sought to be faithful to God throughout her life even though she knew it would be difficult. She is a model disciple...