Original sin
Original sin is the Christian doctrine that each human being is born in a state of sin inherited from the first man, Adam, who disobeyed God in eating the forbidden fruit (of knowledge of good and evil) and, in consequence, transmitted his sin and guilt by heredity to his descendants. The doctrine was defined by Augustine of Hippo (354–430 AD). Engaged in a controversy with the monk Pelagius over the question of whether infants could sin (Pelagius said they could not and therefore would not go to hell if unbaptised), he inserted original sin and the fall from grace into the story of the Garden of Eden and Paul's Letter to the Romans. Augustine identified male semen as the means by which original sin was made heritable, leaving only Jesus Christ, conceived without semen, free of the sin passed down from Adam through the sexual act.