One of the more common objections to the doctrine of original sin is that it's unjust. I didn't eat the fruit, why do I have to suffer? We of course did not eat the fruit, nor does God look at us as if we did. Rather, we are closely associated with Adam and in Adam all die.
This idea or federal headship is similar to the idea of families or nations suffering together for something their leader did and the bible gives us plenty of examples of this happening.
Canaan was curred for for Ham's sin. Genesis 9:25 Then he said: “ Cursed be Canaan; A servant of servants He shall be to his brethren.” God visits the iniquities of fathers on their children - Exodus 20:5 you shall not bow down to them nor serve them. For I, the LORD your God, am a jealous God, visiting the iniquity of the fathers upon the children to the third and fourth generations of those who hate Me. Achan's family was stoned for his sin - Joshua 7:24-26 Then Joshua, and all Israel with him, took Achan the son of Zerah, the silver, the garment, the wedge of gold, his sons, his daughters, his oxen, his donkeys, his sheep, his tent, and all that he had, and they brought them to the Valley of Achor. 25 And Joshua said, “Why have you troubled us? The LORD will trouble you this day.” So all Israel stoned him with stones; and they burned them with fire after they had stoned them with stones. Jeroboam's house suffered for his sins - 1 Kings 14:10 therefore behold! I will bring disaster on the house of Jeroboam, and will cut off from Jeroboam every male in Israel, bond and free; I will take away the remnant of the house of Jeroboam, as one takes away refuse until it is all gone. Same with David's children - 2 Samuel 24:15-17 So the LORD sent a plague upon Israel from the morning till the appointed time. From Dan to Beersheba seventy thousand men of the people died. 16 And when the angel stretched out His hand over Jerusalem to destroy it, the LORD relented from the destruction, and said to the angel who was destroying the people, “It is enough; now restrain your hand.” And the angel of the LORD was by the threshing floor of Araunah the Jebusite. 17 Then David spoke to the LORD when he saw the angel who was striking the people, and said, “Surely I have sinned, and I have done wickedly; but these sheep, what have they done? Let Your hand, I pray, be against me and against my father’s house.” Likewise, son's went into captivity for the sins of their fathers - Lamentations 5:7 Our fathers sinned and are no more, But we bear their iniquities. And Ahab's family suffered for his sins - 1 Kings 21:29 “See how Ahab has humbled himself before Me? Because he has humbled himself before Me, I will not bring the calamity in his days. In the days of his son I will bring the calamity on his house.”
So again, it's not that we ate the fruit, rather we are associated with Adam. The good news is that association is a two way street and Christ pays the price for those associated with Him. This is the relatioship between a corporate head and it's body.
Now there is some variety among those who hold to original sin. Some people say we share in Adam's guilt, others say we only share in his punishment, still others say we are only 'colateral damage' - making a sharp distinction between punishment and suffering. This probably stems from minor variations in the way we understand justice. But the basic picture of suffering due to association is clearly biblical.