The teaching sounds harsh until you look at the world (and your own heart). Then it sounds like a description of reality.
What everyone observes
Human beings come into the world inclined toward selfishness, capable of cruelty, unable to live up to their own ideals. No one has to teach a toddler to lie or grab. Something has gone deeply wrong with us — before any individual decision is made. The puzzle is not whether something is broken; it's how to name it.
The biblical picture
Genesis 3: Adam and Eve's disobedience introduces death, alienation from God, shame, fractured relationships, and a wounding of the divine image in humanity. Paul develops this in Romans 5:12–21 and 1 Cor. 15:21–22: "In Adam all die; in Christ all will be made alive."
The whole human race is in some kind of solidarity with Adam — and now offered a new solidarity in Christ.
Two ways to read it
Western (Augustinian, Catholic, Protestant): humanity inherits both Adam's guilt and his fallen nature. Often paired with the language of "original guilt" — born condemned, unable to save ourselves, requiring baptism and grace for salvation.
Eastern Orthodox: we inherit Adam's mortality, his wounded nature, his susceptibility to the passions and to death — but not his personal guilt. We are born sick, not born condemned. The image of God in us is wounded but not erased. We commit our own sins because of our wounded nature; we are not held guilty for what Adam did.
This is sometimes called the difference between the Augustinian and the "ancestral sin" framework. Fr. John Romanides argued strongly for the Eastern reading.
"Is it fair?"
The Eastern frame mostly defuses the question. You are not held guilty for what someone else did. You do, however, inherit a broken nature in a broken world — in the same way children of an alcoholic inherit a harder family environment they didn't choose, or children born into a war-torn country inherit consequences they did not personally cause.
That is not fairness or unfairness; that is how solidarity works. Humans are not isolated atoms. We are profoundly interconnected — for good and for ill. Adam's fall changed the family we were born into. Christ's resurrection changes it back.
The good news
Christ is the New Adam (Rom. 5; 1 Cor. 15). What Adam broke, Christ heals. What Adam lost, Christ recovers — and gives back more than was lost. Baptism is our entry into Christ's death and resurrection; the image of God in us begins being restored; the journey of theosis (becoming like God) begins.
The Orthodox Easter hymn: "Christ is risen from the dead, trampling down death by death, and upon those in the tombs bestowing life." That is the answer to original sin. Death itself has been trampled.
C.S. Lewis on the doctrine
Lewis: "Christianity is a fighting religion. It thinks God made the world… that human beings have done something to spoil it, and that there's a real war going on." Original sin names the spoilage; the Gospel names the war's outcome.
The Orthodox lens
Every infant carries the consequences of the Fall — mortality, the inclination to the passions, a world disordered by sin. But no infant is born guilty. Baptism is not erasing personal guilt the baby never had; it is grafting the child into Christ's resurrection life, fortifying the wounded nature, and beginning the journey of healing.
St. Athanasius, On the Incarnation: "He became man that we might become god." The Fall is real. The healing is greater.
A pastoral word
If you have ever felt broken before you chose to be broken — disproportionately angry, selfish, anxious, ashamed without knowing why — Christianity has been describing that feeling for two thousand years. You are not crazy. You are not without hope. The same Lord who entered Adam's mortality entered yours, and he is undoing it from the inside, day by day, breath by breath.