Noah was a righteous man. He feared God. He was not a drunkard as some suppose. The wine that he drank fermented due to the drastic change in the atmosphere; the rising of the normal temperature aided the microbes to produce alcohol. Noah, unaware of this, drank it and fell into an inebriated condition.

Ham probably insulted Noah (exposing father’s nakedness is lying with the mother, to show one’s dominance?) resulting in a curse on his descendants. The mutant sinful dormant gene became active in Ham.