What is this doctrine? Original sin is the Christian doctrine which says that because of the sin of Adam and Eve, original innocence is lost and all subsequent human beings are born into a state of sinfulness. The doctrine states that human beings do not commit this sin but rather contract it from the fall of Adam and Eve. That babies are sinners from the moment of conception. The biblical basis for the belief is claimed to be found in Genesis chapter 3, in a line in Psalm 51:5, and in Paul's Epistle to the Romans, 5:12-21 along with a few other scriptures. But it's nonsense and addressing this misunderstanding is not difficult at all. 

First, there is a difference between an urge to do or think something, and actually doing something. Since this is about “SIN” we need to biblically define what “SIN” is by scripture. (1 John 3:4) 4 "Everyone who practices sin practices lawlessness as well. Indeed, sin is lawlessness." So breaking God's laws or commands is sin. So this is an ACTION. Now we know logically what we are dealing with. (Sin is the action taken to break God's laws or commandments) Salvation is depended upon following these laws and not sinning. God's laws are also through Jesus our lord which explains why (Hebrews 5:9) says "He became the source of eternal salvation to all who obey Him." (Matthew 15:18-20)  Explains, out of the heart comes evil thoughts.  14“But each one is tempted when by his own evil desires he is lured away and enticed. 15 Then after desire has conceived, it gives birth to sin; and sin, when it is full-grown, gives birth to death.” (James 1:14-15) Again this is one being lured away and this desire then becomes an action, this action is breaking God's commands. 

Now lets deal with some scriptures that try to prove we are born with sin inherited.

(Isaiah 53:6) 6 We all like sheep have gone astray, each one has turned to his own way; and the LORD has laid upon Him the iniquity of us all.”  and (Psalms 58:3) "The wicked are estranged from the womb; the liars go astray from birth." You will notice they say “gone astray,” “turned to his own way” and “ liars go astray,” again this is ACTION not inherited. A baby can't lie from the womb, this is a choice for the child to eventually lie.

(Romans 7:15-17) 15 "I do not understand what I do. For what I want to do, I do not do. But what I hate, I do. 16 And if I do what I do not want to do, I admit that the law is good. 17 In that case, it is no longer I who do it, but it is sin living in me that does it." These scriptures are all about doing, again…ACTION. For we are to live in the spirit of Christ and not the flesh. That is why the next scripture says 18 “I know that nothing good lives in me, that is, in my flesh; for I have the desire to do what is good, but I cannot carry it out.” He has the desire to do good, but the flesh takes over, and then the action is to sin.

(Romans 5:12) Therefore, just as sin entered the world through one man, and death through sin, so also death was passed on to all men, because all sinned.” Here you will notice that when we sin, we get death, we all die because all have sinned. A few scriptures later, we have the solution. (Romans 5:21)  "so that, just as sin reigned in death, so also grace might reign through righteousness to bring eternal life through Jesus Christ our Lord." This doesn't mean sin is inherited, but death is. This next verse explains it's death. (1 Corinthians 15:21,22) 21 For since death came through a man, the resurrection of the dead comes also through a man. 22 For as in Adam all die, so in Christ all will be made alive. This is death being inherited, not sin. (Romans 5:15-21) Explains how, disobedience by one man (Adam) brought death, and obedience by one man (Jesus) brought life.

(Romans 8:1-11) Is all about walking in the flesh or the spirit. Again, this is ACTION, not inherited sin. (Romans 8:12-14) 12 Therefore, brothers, we have an obligation, but it is not to the flesh, to live according to it. 13 For if you live according to the flesh, you will die; but if by the Spirit you put to death the deeds of the body, you will live. 14 For all who are led by the Spirit of God are sons of God." Living by the spirit is living without sin. This is action. This is also expressed in (Ephesians 2:1-10) we were dead in our trespasses (breaking God's laws). Action not inherited.

Foolishness can lead to sin. These are also both actions. (Proverbs 22:15) 15 ”Foolishness is bound up in the heart of a child, but the rod of discipline drives it far from him."  Understanding again, this is of the heart and we are to use reason refrain from sinning.

A scripture used to help push the Original Sin doctrine is David's poetic confession. (Psalms 51:5) “Behold, I was brought forth in iniquity, and in sin did my mother conceive me.” This is missunderstood that he had sin from the womb, when it should be understood that his mother conceived him while sinning. It's not to be taken literally anyway, but let's say we did and it was David's sin in the womb. You would run into a major problem a few scriptures later (Psalms 51:12) of the same Psalm. “Restore to me the joy of Your salvation, and sustain me with a willing spirit.” The word “Restore” or “Return” means he once had joy of salvation and willing spirit. This means that he didn't have sin from birth. This scripture debunks it no matter how you view, literally or not.

Genesis chapter 3 expresses the first sin by Adam & Eve, of course again, ACTION to eat the fruit and disobey God. Some will try to bring up (Genesis 3:15) 15 "And I will put enmity between you and the woman, and between your seed and her seed. He will crush your head, and you will strike his heel." There is nothing here about inheriting sin. This would be hard to take literally anyways, if you say the seed is literal, then you would literally have to explain who Satan's seeds are. This is seen as a spiritual battle between Satan's evil spiritual fruit and the woman's righteous spiritual fruit. That has been the battle since the first lie. This was between Satan and Eve and perhaps is why Adam is not in this discussion for it was Eve who offered the fruit to Adam.

It is clear that Sin is an action chosen by will, even though our desires get the best of us walking in the flesh. 

(Ezekiel 18:20) 20"The soul who sins is the one who will die. A son will not bear the iniquity of his father, and a father will not bear the iniquity of his son. The righteousness of the righteous man will fall upon him, and the wickedness of the wicked man will fall upon him." This shows it is not carried from father to son.

Every example shows sin is an Action taken, not inherited.