Mary was Immaculately Conceived
The Church teaches that Mary was Immaculately conceived. This means that, from the moment that she was conceived, she, unlike us, had no stain of Original Sin on her soul (as we inherit from the Fall of our first parents, Adam and Eve), meaning that she was not going to be eternally separated from God and did not have inclinations to sin. In Baptism, we are cleansed of the eternal punishment Original Sin, but we still have a tendency to sin. Mary never had either of those attributes. God kept her free from Original Sin because it was fitting that a sinless woman should bear His only Son, Jesus Christ, in her womb. Some skeptics might also assert that this doctrine was taken out of thin air in 1854. The Church defined the dogma of the Immaculate Conception in 1854. However, the early Church believed this doctrine essentially unanimously. Numerous Church Fathers testify to it. But why was this not defined as infallible until 1854? The Church often only defines dogmas when they are being disputed.
For example, the Church did not define the Holy Sacrifice of the Mass as a sacrifice until the Council of Trent in the sixteenth century, when Protestants began to deny the Mass’ sacrificial quality, despite the Church holding this as the central teaching since her first years. Another common objection to the Immaculate Conception is that if Jesus Christ had to be conceived by a sinless woman, then would not that sinless woman have to have been conceived by a sinless woman, who would also have to be conceived without sin, etc.? No, because God is all-powerful and the Immaculate Conception was not necessary, even though it was fitting. Jesus Christ, the King of kings and the Lord of lords, could have been born of a sinful woman or even just appeared on the earth without being born. However, it was fitting to His Majesty that he be born of a sinless woman. Also, St. Anne (Mary’s Mother) gave birth to a person (although the best of the human race) who is infinitely less than Jesus Christ. Therefore, this infinite difference (birth to mere human versus birth to God) and the fact that the Immaculate Conception was not necessary, but fitting, reveals how it was not necessary for the woman ancestors of Mary to have been conceived without sin.
Finally, though the truth is not necessarily found explicitly in Scripture, some opponents of the Immaculate Conception will assert that there is no biblical basis for this teaching. However, in Genesis 3:15, God puts enmity (total opposition) between the woman and satan, and between the woman’s offspring and satan’s offspring. The total opposition between the woman and satan implies that the woman is totally free from satan’s influence, implying that sin does not affect her at all. Moreover, the Lord says in Genesis 3:15 that the woman’s child “will strike at” satan’s head, while satan will “strike at [the child’s] heel.”