The Adam and Eve story passed through many hands before being written down in its present form.
The story contains at least three different theories overlaid one atop the other.
1.Disobedience.
2.Sex
3.Trickery and deceit
1.Disobedience at going against the injunction to leave the fruit alone. (Blame from one character passed to the next.)
2.The "fruit" becomes metaphorical sex and this is revealed in the pair covering themselves in shame.
3.The serpent deceiving the woman and enticing her with the reward of knowledge and power.
As the Jewish people grew more sophisticated about theology the rabbinical explanations took in more feasible areas of ethical justification for condemning the human race.
Moreover, the very idea that misbehavior (sin) could be genetically transmitted from parent to child bespeaks ignorance and naivete befitting a primitive people.
After all, the idea was once pervasive that a child could take on characteristics according to how the mother acted and determined by what the mother saw has continued up to fairly recent times. Children were superstitiously thought to be susceptible to being "marked" by some unwitting activity by the mother.
This was thought to be true about animals and people.
Original Sin is not just one belief, but; many.
The Bible is quite confused about what this is because so many ideas have been stirred into the pot over time and explanations at one layer seem to contradict later ideas grafted on by more enlightened thinkers.
Even today--you'll find many theories as to what Original Sin might have been.
It isn't crystal clear because it is a hodge-podge mythology subject to constant revisions.
The idea, for example, that Satan was the "original serpent" is a late explanation. The jews didn't really have a Satan until they were carried off to Babylonian ideas and returned to rebuild their theology with colorful late additions.
So too--blaming women because of Eve is rather peculiar idea as well. Adam was the CEO of the human family and his leadership stunk. Yet, the woman, Eve acquires most of the culpability.
The story is a very handy way (and always has been) of justifying social "norms" and prejudices against sex and women.