I moderate an international forum for a muscle disease caused by various mutations in the chloride channel of the skeletal muscle. In many of these types of diseases there is something called the "Founder Effect" which means everyone with a particular mutation can trace their ancestry back to one person.
In terms of spiritual genetics, Adam was the "founder" of our mutation which was passed on and caused us all to be affected. It doesn't seem fair to some people, just as genetic mutations in the physical realm don't seem fair...we didn't ask for it and didn't do anything personally to bring the sentence of death on ourselves, but because we inherited that defect we are all born with the same sin nature.
The good news is that we have gene therapy! Our donor, Jesus, has the perfect and complete gene that is injected and overcomes the defect (sin) that was sending us toward a certain spiritual death.
Hallelujah!
Jan