Not only am I a Protestant, but a born again Holy Spirit filled one to boot.
So this is a centuries old dogma huh? Depending on how you want to count this dogma it will either be
one century old in about 44 years (2054) or it is 154 years old. The Immaculate Conception was solemnly defined as a dogma by Pope Pius IX in his constitution Ineffabilis Deus, published December 8, 1854 (the Feast of the Immaculate Conception), and consecrated by Pope Pius XII in 1942. The dogma was rejected by the Orthodox Church in 1854. According to the dogma, Mary was conceived by normal biological means, but her soul was acted upon by God (kept "immaculate") at the time of her conception.
The Catholic Church believes the dogma is supported by scripture (e.g. her being greeted by Angel Gabriel as "full of Grace"), as well as either directly or indirectly by the writings of many of the Church Fathers, and often calls Mary the Blessed Virgin (Luke 1:48). Catholic theology maintains that since Jesus became incarnate of the Virgin Mary, she needed to be completely free of sin to bear the Son of God, and that Mary is "redeemed 'by the grace of Christ' but in a more perfect manner than other human beings." (In other words find a scripture then wrap a false belief around it.)
So contrary to what the scriptures say, God does show favoritism after all (or at least He did to Mary!) Romans 2:11 and Acts 10: 34 says, "For God does not show favoritism."
So was Mary the only person in the bible who was "full of grace?" No. Acts 6:8 says "Now Stephen, a man full of God's grace and power, did great wonders and miraculous signs among the people." While Mary claims in Luke 1:48 that "...all generations will call me blessed" the term blessed is used 67 other times in the NT alone. To be called blessed is hardly unique. Yes she was chosen by God to be the vehicle to carry His Son, but beyond that she was just an ordinary woman. She says of herself that she is of "low estate" and a "handmaiden" in Luke 1:48.
I believe the reason the sin nature was not present in Jesus is because the sin nature is passed down through the father of the baby not the mother. So since God was the father of Jesus He couldn't have the sin nature.
LST