The second Article of Faith of The Church of Jesus Christ of Latter-day Saints concerns the concept of “original sin:”
We believe that men will be punished for their own sins, and not for Adam’s transgression.
Simply put, Latter-day Saints believe that when a child is born, she is innocent and pure. She does not need baptism until she reaches an age where she is capable of understanding right and wrong. The following scripture from the Book of Mormon explains this:
And their little children need no repentance, neither baptism. Behold, baptism is unto repentance to the fulfilling the commandments unto the remission of sins. But little children are alive in Christ, even from the foundation of the world (Moroni 8:11-12)
In the church, children are not baptized until they reach the age of eight, which is considered the age of accountability—in other words, the age in which they are fully aware of their actions. However, there are even exceptions in this case. Those born with limited mental capacities are considered innocent and baptism is not necessary for them. In fact, teachings suggest that these individuals were so righteous in their pre-earth life, the only requirement necessary to fulfill their eternal exaltation was to come to earth to receive a physical body. Their presence here on earth is a way for God to help us who have all our faculties gain Christlike qualities of love and service.
Latter-day Saints do not believe in the concept of original sin because the transgression of Adam and Eve in the Garden of Eden is seen as part of Heavenly Father’s plan for our eternal progression. Because when Eve, then Adam, ate from the Tree of Knowledge, they became mortal beings, able to choose right from wrong—but most importantly, able to bear children:
And now, behold, if Adam had not transgressed he would not have fallen, but he would have remained in the garden of Eden. And all things which were created must have remained in the same state in which they were after they were created; and they must have remained forever, and had no end. And they would have had no children; wherefore they would have remained in a state of innocence, having no joy, for they knew no misery; doing no good, for they knew no sin. But behold, all things have been done in the wisdom of him who knoweth all things. Adam fell that men might be; and men are, that they might have joy. (2 Nephi 2:22-25.)
In other words, the fall was necessary part of God’s plan for us:
“Adam and Eve were two of the noblest children of God. For this reason they were chosen to come to earth and to initiate mortal life for others of God's children. Just how God brought about man's life on earth, we do not know. The Bible is a deeply religious account of creation, not a scientific record. The story of the fall of man in scripture is an effort to explain the divine origin and purpose of life and should be read with this thought in mind. The story is brief and somewhat figurative and symbolic in language, but from it we can glean a few fundamental religious convictions. Latter-day Saint scriptures have thrown additional light on the creation story. Adam and Eve were not sinners in the traditional sense of the word. We believe God gave them a choice of remaining in their premortal state or of taking on mortality with its attendant opportunities and suffering. They were given a choice between two conditions. They could obey the laws of their premortal natures and remain free from death and moral responsibility associated with mortality, or they could become mortal and subject to death and learn the hard lessons of life. Adam and Eve chose the courageous role, the one God wanted them to choose. They "broke" the law of their premortal life, becoming mortal, or subject to death. The Bible says they partook of the fruit of the tree, of which God had said, "Ye shall not eat of it, neither shall ye touch it, lest ye die." (Genesis 3:3.)Just how they became mortal, we do not know. But of one thing we are sure: they were not sinners. They chose to leave the presence of God and walk by faith, to learn to cope with the laws and forces characteristic of earth life. They "fell" in the sense that they left the presence of God and became subject to the limitations of mortality, including death, ignorance, and sin. Adam's first choice, as we have seen, was to become mortal or to remain immortal. His second choice was either to remain in ignorance or to receive knowledge and thus become a moral, responsible son of God. He chose the latter alternative. As Latter-day Saints, we honor Adam and Eve because they had the courage and faith to become mortal and also to assume moral responsibility. We believe that in making these two choices, they were doing God's will and initiating the same two great experiences for us, their posterity.” ( Best of Lowell L. Bennion: Selected Writings 1928-1998, p. 97)
“Latter-day Saints view the Fall with an optimism that is uncharacteristic of most of the Christian world. It is an optimism born of the conviction that Adam and Eve went into the Garden of Eden to fall, that the Fall was as much a part of the foreordained plan of the Father as the Atonement. We believe they did precisely what needed to be done, that the Fall "had a twofold direction—downward, yet forward. It brought man into the world and set his feet upon progression's highway" (Orson F. Whitney, in Cowley and Whitney on Doctrine, 287). Because of this, we do not speak of our first parents' actions in Eden as sin: theirs was a transgression. Because of this, we do not believe in a doctrine of human depravity, that men and women are essentially so vile, so morally filthy, that they simply cannot choose to do good. Because of this, we do not believe in an original sin that entails upon the posterity of Adam and Eve, an original sin that requires infant baptism. Rather, through modern revelation we know that by virtue of the atoning sacrifice of our Lord and Savior, God forgave Adam and Eve their transgression in Eden, such that "the sins of the parents cannot be answered upon the heads of the children, for they [the children] are whole from the foundation of the world" (Moses 6:54). In other words, the posterity of Adam and Eve—including all of us who live some six thousand years after the Fall—are neither responsible nor accountable for what Adam and Eve did.” (Robert L. Millet, Alive in Christ: The Miracle of Spiritual Rebirth, p.11-12)
Members of the church revere Eve not only as “the mother of all living,” but as a courageous daughter of God. She and Adam were willing to suffer the Fall in order to begin the process of bearing children, thereby enabling other spirits to come to earth. Jesus Christ offered to be the Savior, atoning not just for Adam and Eve’s transgression, but for all children who desired to return to God’s presence.