Is there a original sin ?
The key to Christian and especially Missionary Christian doctrine is the concept of Original Sin, namely that all mankind is condemned to death and eternal torture in Hell because of the sin of the original two people who disobeyed God and ate of the fruit of knowledge of good and evil.
The teaching goes that God cursed them and all future generations and their act introduced death into the world.
And there is nothing we can do about this inherited curse of our own accord. We are condemned from the moment of our birth and need a savior to rescue us. Left to our own devices we are literally, "Damned if we do and damned if we don't."
Okay, let's follow the golden rule of Torah study:
don't quote a single sentence "proof text", read the whole section. What really happened here? (Please read Genesis Chapters 2 and 3. Come on, it just takes a few minutes.)
Now off to the first curse, the snake. Notice verse 15, Chapter 3, "I will put enmity between you and the woman and between your offspring and hers...." 
Clearly the curse directed at the snake is eternal, given this reference to future generations. And it is a curse as verse 14 says,
"Because you did this, more cursed shall you be..."
Now look at the sixteenth verse, the alleged "curse" of the woman. Do you see the word "curse" there anywhere? No, because it is not there. The woman was punished for her acts but not cursed.
On to Adam (Chapter 3, verses 17 -20). The word "cursed" appears in this section, right? Yes, but look at verse 17, "Cursed be the ground because of you." Not "Cursed be you." [italics mine] Big difference.
Adam was going to have to farm (work hard) for a living but absolutely no curse was applied to him directly. It didn't happen. Period.
So we don't have a curse? Wasn't the punishment eternal?
Check again. I've pointed out the reference to future generations in the curse of the snake. There is absolutely no reference to future generations in the punishments of Adam and Eve.
Wasn't this somehow implied?
Well, look at some other sections. When God meant something to be eternal, He said so. Look at Chapter 17, verse 7 which gives the time span of God's covenant with Abraham, "I will maintain My covenant between Me and you, and your offspring to come, throughout the ages, to be your God to you and to your offspring to come."
So God was perfectly capable of assigning a time frame, even an eternal time frame, to His actions when He wanted to. Obviously, a Supreme Being Who made the eternal nature of His blessing through Abraham so clear would have made the eternal nature of any curse through Adam equally clear.
But can't we prove the existence of some sort of eternal curse since Adam and Eve brought death to all mankind?
Look at God's pronouncement of Adam's "death sentence" in verse 17, "For dust you are, and to dust you shall return."
So Adam and Eve were created with eternal life and then cursed with death, right? Surely their action is the reason we all must die?
Wrong . Adam and Eve were born mortal. Note verse 17 does not says "Dust you have become" it says "Dust you are."
They never had eternal life in the first place. Then check out verses 22 through 25. God says (presumably to the angels) regarding Adam, "What if he should stretch out his hand and take also from the tree of life and eat, and live forever?"
In other words there was an action which Adam had not yet performed which was required for Adam to sustain his Body and receive an eternal nature.
And what did God do after this statement? He drove Adam out of the garden and placed an angel with a flaming sword to guard the tree of life. In other words, Adam never had an immortal nature to lose. He was simply placed in a position where his mortal nature continued.
let me explain it again :
God placed an angel to guard the tree of life to prevent Adam and Eve from eating from it for the simple reason that if they had begun to eat from this tree their mortal natures would not have effected them . No Tree of Life = No immortality . We never had an immortal nature .
The bottom line is that there never was any curse of original sin. Therefore never any need for anyone to die for us to remove such a curse. We are each responsible for our own actions and our own individual relationship with God.