Original Sin deals with Adam's sin of disobedience in eating from the Tree Of Knowledge of Good and Evil and its effects upon the human race. It is defined as "that sin and its guilt that we all possess in God's eyes as a direct result of Adam's sin in the Garden of Eden." The doctrine focuses on its effects of our nature and our standing before god, there are three main views that deal with that effect.
Adam's sin had no effect on his descendants other than those who choose to follow him. According to this view, the man has the ability to stop sinning if he chooses to.
Adam's sin has resulted in the rest of mankind to inherit a tendency to sin, commonly referred as to having a "Sin Nature." The sin nature causes us to sin naturally. According to this view, we are held responsible for our own sins not Adam's and that man cannot stop sinning on his own.
The doctrine stats that Adam's sins has resulted in humans having a sin nature, and our guilt before God in which we deserve punishment. This doctrine has two main views, one view states that the human race was within Adam's in seed for; thus when Adam sinned, we sinned him. The other main view is that Adam served as our representative so, when he sinned, we were found guilty as well.