There is nothing of any doctrines of the Fall and original sin in the Nicaean creed of 325 AD defining Christianity. Thus the Christian doctrines of the Fall and original sin are a wide spectrum. For most the fall is an alteration in the relationship with God and the original sin is an event with negative consequences for all of mankind. It is certainly not a teaching that humans were created with a tendency to commit sin but quite the opposite, that human beings were created to do good and sin is a contamination and corruption of that.