By Adam's transgression came death upon all flesh, but sin did not automatically come upon all flesh, action is required and little children are exempt from sin, not fully comprehending the concept of sin until they are eight years old, at which time God holds them accountable for the sins THEY commit, not for the sins ADAM committed...
Holding someone accountable for antother's sins is a doctrine of a devil....
We are only accountable for the sins we KNOWINGLY commit...
All those who have not had the law explained to them or who cannot comprehend the law, such as little children and mentally challenged individuals, are exempt from the law...
Matthew 19: 14
But Jesus said, suffer the
little children, and forbid them not, to come unto me: for
of such is the kingdom of heaven.
D&C 29: 46-47
46 But behold, I say unto you, that little children are redeemed from the foundation of the world through mine Only Begotten;
47 Wherefore,
they cannot sin, for power is not given unto Satan to tempt little children,
until they begin to be accountable before me;
D&C 74: 7
But
little children are holy, being sanctified through the atonement of Jesus Christ; and this is what the scriptures mean.