A quote from George Murphy about Adam, Eve, and the first sin:
The latter view, in which humanity was created in an immature condition and expected to grow, corresponds best to our scientific picture. The earliest human sin was not a fall from perfection but a start along a path that led away from God.
The first humans would have inherited tendencies for selfish behaviors that injured their fellows. Sin has to do with our relationship with God, and didn’t exist before God revealed his will to our ancestors. But when God told them not to harm others, they would have been tempted to ignore him.
Humanity could theoretically have obeyed God, for our behaviors are not hardwired. Sin wasn’t “necessary” but was “inevitable.” Refusing to obey God, humanity turned from God’s intended goal and started on a road to perdition. Science of course supplies further details about early humanity, but we’re concerned here with theology rather than history.
This corresponds to the picture we get from Genesis.