Michael Horton, in The Christian Faith (p. 427-428), has some fascinating insights on the doctrine of original sin:
“The tendency of fundamentalism is to reduce sin to sinful acts and behaviors, while liberalism reduces sin to evil social structures that impede the realization of the ethical kingdom. In contrast to both forms of reductionism, the biblical understanding of sin is far deeper in its analysis. Sin is first of all a condition that is simultaneously judicial and moral, legal and relational. Accordingly, we sin because we are sinners rather than vice versa. Standing before God as transgressors in Adam, we exhibit our guilt and corruption in actual thoughts and actions. If we cut off one diseased branch, another one–pregnant with the fruit of unrighteousness–grows in its place.
Furthermore, we are both victims and perpetrators. There is no human being since the fall who is only a victim; yet it is also true that every sinner is also sinned against. Such is the solidarity of humanity under the curse of the violated covenant of creation. A particular act of sin may be (or include) the fault of someone else, but the sinful condition and the web of sinful actions and relationships that flow from it implicate us as well. It is true that we do not simply choose our vices, but are conditioned by the sinful structures to which our particular socio-cultural or familial contexts tend. Yet it is also true that we yield ourselves to these vices and are responsible for our own actions. Simplistic theories of sin easily identify the ‘righteous’ (us) and the ‘wicked’ (them), but as the biblical drama unfolds we recognize with increasing clarity that ‘all, both Jews and Greeds are under sin, as it is written: “None is righteous, no, not one; no one understands; no one seeks for God. All have turned aside; together they have becomes worthless; no one does good, not even one”‘ (Ro 3:9-12).