In Catholicism, there's the idea of original sin. Original sin means that you're born sinful because of what Adam and Eve did, which was eating the fruit from the Tree of Knowledge of Good and Evil a.k.a. the Forbidden Tree.

We all know the story of Adam and Eve, especially if you read Paradise Lost. Adam and Eve are the first two people God created and were made carefree and happy all the time. They were told by God that they could do anything they wanted except eat from the Tree of Knowledge of Good and Evil. However, when Eve was alone, Satan (who possessed a snake because of its subtlety) tricked Eve into thinking that God wouldn't kill them because the snake "ate" the fruit and he was still alive. So, Eve grabs the fruit and eats it. Then, she tells Adam and he decides he would never want to be separated from her so he eats it too.

Ever since then, we've all been born into sin and are doomed to die because they introduced Sin and Death into the world. But, the problem with all of this is that it's unjust. The reason it's unjust is that we are all being punished for something we didn't do. If God was really fair like he's supposed to be, why is he condemning me for something that two other people did thousands of years ago? Think about it, the second you're born, you're a sinner. You just got out of the womb and you're already going to Hell. Why? You didn't do anything and you can't make decisions or really think yet. You don't even have the means to commit a sin, but you're already damned. Any logically thinking human being would agree that this is completely inequitable.