the reason Mary was proclaimed by the Catholic church as the Immaculate Conception is because she is believed to have been born without sin. Why? because she is to carry Jesus Christ for 9 months and thus she has to be spotless. Here is the biblical basis; St Gabriel's greeting to Mary before she conceived Jesus was," Hail Mary FULL OF GRACE, the Lord is with you". What does full of grace meant? When you have a cup that is full of water, is there space for additional water, none, right? So Mary who is full to the top of grace has no sin, no original sin. What are the causes of sins; greed, pride, laziness, etc. Mary does not have those tendencies. God has already protected her from all those tendencies, she was favored by God. So those who accuse us Catholics of favoring her more than Jesus Christ are all wrong. Mary does not have pride, greed. She will bring all prayers to her Son, Jesus Christ. Lastly, if we believe that the Holy Spirit continues to guide us to the truth up to now as the Bible has said, well read the story of St. Bernadeth, Bernadeth asked Mary who she was during Mary's apparition, Mary said, I AM THE IMMACULATE CONCEPTION, Bernadeth did not know anything about that teaching of the church and the Catholic church at that time did not proclaim Mary as the Immaculate conception. As the story went...... with all the troubles the church was suffering caused by the apparition of Mary to Bernadeth, the bishop asked Bernadeth to ask the lady who she is. Many believed the lady came from the devil but Bernadeth said no adamantly, it cannot be from the devil since she is so beautiful, clothed with the sun, so kind, so understanding, so gentle. Bernadeth who was a little forgetful did not want to forget the lady's name so she said the words over and over, I am the Immaculate Conception, till she arrived to the place of the bishop. The bishop was amazed because at that time the church was debating if Mary should be proclaimed the Immaculate conception. See, the story of Bernadeth is a great great evidence that the Holy Spirit continues to guide the church up to now to all truths, wether you non- Catholics believe it or not.