Have you ever considered it unfair that we are each born in original sin, because Adam and Eve sinned back in the Garden of Eden? Welcome to the human race. I believe we have all had that thought at least in passing.
LAB notes say it this way: How can we be declared guilty for something Adam did thousands of years ago? Many feel this isn't fair; however, each of us confirms our solidarity with Adam by our own sins each day.
Our nature is prone to rebellion. It doesn't take long for new parents to realize that their "perfect" newborn might be a bit strong-willed and selfish. How often is "no" the first word out of a child's mouth! Although sin entered the world through Adam and Eve we are each responsible and accountable for our own sin. Even though we may think it isn't fair we are sinners and we don't really want or need fairness - we want and need grace and mercy.