After thinking about this question, I think it may be far deeper reaching in its consequences than you may have expected. Not only that, but there is a huge amount of background knowledge in Christian doctrine that goes into addressing such an issue. As well as this, it has been a debated (as if anything hasn't been) issue over the history of the church. I fear that I will raise more questions than I will answer. Nevertheless lets jump in and have a look at some of the issues we are dealing with.
I take it that the reason you have posed such a question (and inform me if I have assumed incorrectly) is essentially because of this problem, namely "
how can God hold every person responsible for the original sin adam committed?" I will refer to this problem as [R] from here on to make referencing easier.
I have avoided taking your original question at face value because I don't think you really want to examine how it is possible (physical, spiritually or otherwise) for sin to be passed on. Such discussion would lead right into discussion of salvation and Jesus paying penalty for our sins. An interesting discussion to be sure (and also one I feel quite under qualified in tackling
) but I don't think this is at the heart of what you are asking.
The Fall
As a Christian, it seems to me that I am tied to the belief in a historical fall. That is to say that Adams original sin was a historic event that occurred in real life at some point in the past. As you know of course, this original sin is what most theologians refer to when they talk of "the fall" - the fall from sinlessness into the sinful. Now at the time of the fall, we note that sinfulness wasn't just a meaningless inconsequential new name for human existence. It represented a real change - most notably death, awareness of objective morality and a pre-disposition toward sinful acts.
Now in addressing [R], we must ask what, if anything, are humans today responsible or affected by in regard to this original sin? Unquestionabley of course, is the fact of death and to a lesser extent, awareness of objective moral values. Certainly this shows that we are still affected by the fall, but does it implicate us in responsibility for it? That is, are we held responsible for the sin adam, a completely different person, committed however long ago? The reasons associated with answering this question will make much headway in answering [R]
Typically, proponents of the affirmative to this question will say that the
total depravity of man entails that man is guilty and in need of redemption from birth. The best verse I could find in my light research for you was:
Psalms 58:3: "The wicked are estranged from the womb; they go astray from birth, speaking lies."
However, such an affirmative view and reading of scripture is not universal amongst Christians. Indeed, I find the waters quite murky. I find it quite reasonable to look at Psalm 58:3 as a reading of how we are affected by our pre-disposition toward sin and not as our involvement in sinful acts before birth.
...
So how does this help us with [R], that is:
"
how can God hold every person responsible for the original sin adam committed?"
Under this admittedly brief overview of Adams original sin, it remains unclear whether God does hold us responsible for Adams sin at all. Certainly, we don't doubt that this original sin has affected us (death, awareness of moral values and pre-disposition toward sinful acts) but does that imply that we are guilty before any of our own personally sinful acts have taken place? Until I see a robust defense of Adams guilt implicating us in guilt, my instinct answers in the negative. That is, I don't see any good reason for even having to worry about [R]. It is not clear that God does pass on this default guilt state from generation to generation.
More than that, [R] is doubly irrelevant since I have committed sinful acts via my own volition. What good is being concerned about Adams sin, if I know that I have sinned - I am just as fallen as he ever was!