Death is the result of sin in the world. Death is not a direct result of each individual person's sin. I will die someday, not because of any particular sin that I have committed, but because it death is what we have "inherited".
It is not a sin nature that has been inherited. We are born into this world with bodies, but without the Holy Spirit. (John 3:7) Doesn't it make sense that we would follow the inclinations of our bodies apart from the influence of the Holy Spirit?
Here's a link to a very good article on Romans 5:12
http://www.cybertime.net/~d2l/romhtml/rom5b.html
Here's a brief quote from it:
"5:12b. The consequence of Adam's sin is expressed in the next clause of Romans 5:12, "and death through sin." God had given to Adam an explicit command, a prohibition, the transgression of which would result in death. "And the Lord God commanded the man, saying, 'You may freely eat of every tree of the garden; but of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat of it you shall die.'" (Gen. 2:16-17) At the serpent's suggestion Eve ate of the tree and gave it to her husband, Adam, who also ate (Gen. 3:6). Thus did Adam transgress God's command and he died. In what sense did they die that day as a result of their transgression? Obviously they did not die physically. Since they did not die physically that day they must have died spiritually that day. This is apparent from the fact that they hid themselves from the presence of the God (Gen. 3:8) and eventually they were driven out of the garden away from the tree of life (Gen. 3:22-24).
As physical death is the separation of man's spirit (person or self) from his body, so spiritual death is separation of man's spirit from God. It is the opposite of spiritual life, which is a personal relation to God, fellowship and communion with God (John 17:3; 5:24; Eph. 2:1). Spiritual death is separation, alienation, from God (Eph. 4:18; Col. 1:21). It is not something wrong inside of man, but a negative or wrong relation between man and God. Spiritual death is like a barrier or iron curtain between man and God. Death is also a power. It is personified in the Scriptures as a king who reigns over the whole human race. Paul says, "by the offense of one, death reigned through the one" (Rom. 5:17; see also Rom. 5:14). Death as a kingly power separates man from God (spiritual death) and brings about eventually the separation of man's spirit from his body (physical death). Physical death is the outward final expression and natural concomitant of spiritual death (Psa. 88:3-5; Isa. 38:10-19).
5:12c. The effect of Adam's transgression on the whole race of Adam's descendants is expressed in the next clause of Romans 5:12, "and so death passed unto all men." Man today, Adam's posterity, is thus different from Adam himself. As Adam was originally created, he was spiritually alive, walking in fellowship with God. There was no barrier between him and God. But this not true of us, his descendants. We are born spiritually dead and in the process of dying physically. From birth we are in a state of alienation from God. Not because of anything we have done, but because of Adam. Thus "sin indeed was in the world before the law was given, but sin is not counted where there is no law. Yet death reigned from Adam to Moses, even over those whose sins were not like the transgression of Adam." (Rom. 5:13-14) Man is spiritually dead not because of his own sins but because of Adam's sin. This spiritual death along with physical death was transmitted unto all men from Adam.
Note that Romans 5:12 does not say
sin passed unto all men but instead it says that
death passed unto all men. It is death, not sin, that has been transmitted from Adam to his descendants. This verse contradicts the assumption of the doctrine of Original Sin which assumes that it is
sin that has passed unto all men from Adam. Paul, however, teaches in this passage that it is
death, not sin, that is passed unto all men (See also verses 14 -- "death reigned", verse 15 -- "by the trespass of one the many died", and verse 17 -- "by the trespass of the one, death reigned through the one".)
5:12d. The connection between Adam's sin and the sin of his descendants is given in the last clause of this verse,
eph ho pantes hamarton, "because of which all sinned." The interpretation of this clause hangs on the meaning of the Greek prepositional phrase at its beginning,
eph ho. This phrase is made up of a preposition
epi and a relative pronoun
ho. The preposition has several different meanings depending upon the immediate context and the case of the noun or pronoun with which it occurs. Its primary meaning is superposition,
on,
upon. Since the relative pronoun
ho is in the dative case, the metaphorical meaning of
ground, or
reason seems best here for the preposition
epi. Thus it should be translated "on the ground of", "by reason of", "on the condition of", "because of". The meaning of the relative pronoun depends upon its antecedent. In the Greek language the relative pronoun agrees with its antecedent in number and gender. Here the relative pronoun is singular in number but it may be either masculine or neuter in gender. If the relative pronoun
ho is taken as masculine and the word
ho thanatos [the death] in the preceding clause, which is nearest noun in the singular and masculine, is taken as its antecedent, then the prepositional phrase
eph ho would be equivalent to
epi thanato [because of death]. In that case the phrase should be translated "because of which" or "upon which condition." With this meaning given to the prepositional phrase, the whole clause may be translated "because of which all sinned" and interpreted to mean that all men sinned because of death that has been transmitted to them from Adam. In other words, the transmitted death from Adam provides the grounds or condition upon which all men sin. But how is it possible for all men to sin because of death? How does death lead to sin? This may be explained in the following way. Since man is born into this world spiritually dead, not knowing the true God personally, and since man by the structure of his freedom must choose a god, then he will obviously choose a false god because he does not personally know the true God. Since the true God is not a living reality to him, and since he must have a god, man will choose some part or aspect of reality as his god, deifying it. "...they exchanged the truth about God for a lie and worshipped and served the creature rather than the Creator..." (Rom. 1:25). Paul, writing to the Galatians, described this relation of death to sin when he reminded them of their condition before they became Christians. "Formerly, when you did not know God, you were in bondage to beings that by nature are no gods" (Gal. 4:8). Not to "know God" personally as a living reality is to be spiritually dead. And a man is "in bondage to beings that are no gods" when he chooses them as his gods. He is in bondage to them because he does not personally know the only true God, that is, because he is spiritually dead. Thus man sins (idolatry basically) because he is spiritually dead. This relationship between death and sin is what Paul is describing in the last clause of Romans 5:12. Because of death all men sinned. Spiritual death in the case of Adam's descendants leads to sin; not the other way around."