If it was Ham who saw his father's (Noah's) nakedness, why curse Canaan, a grandson? Why specifically Canaan when Ham had three other children, Kush, Mizraem and Phut? Why is the curse a burden to Kush (blacks), when he was never cursed?
“And Noah began to be an husbandman, and he planted a vineyard: And he drank of the wine, and was drunken; and he was uncovered within his tent. And Ham, the father of Canaan, saw the nakedness of his father, and told his two brethren without. And Shem and Japheth took a garment, and laid it upon both their shoulders, and went backward, and covered the nakedness of their father; and their faces were backward, and they saw not their father's nakedness. And Noah awoke from his wine, and knew what his younger son had done unto him. And he said, Cursed be Canaan; a servant of servants shall he be unto his brethren”.
Why did Noah curse Canaan when it was Ham who saw him naked? Why was Noah so angry that Ham saw him naked? Some propose that Ham and/or Canaan actually did something to Noah in addition to seeing him naked. The passage mentions that Noah was angry when he found out “what his youngest son had done to him.” Any theory of what occurred is speculation.
Another view arises out of comparison with Leviticus 20:11, "And the man that lieth with his father's wife hath uncovered his father's nakedness: both of them shall surely be put to death; their blood shall be upon them." With Leviticus 20:11 in mind, it is proposed that Ham had sex with Noah's wife, and that was what brought the curse from Noah. However, this figurative understanding of "uncovering nakedness" fails to account for the fact that Shem and Japheth walked into the room backward and covered Noah with a garment. This does not make any sense if "uncovering nakedness" means "having sex with Noah's wife." It definitely seems that Noah was lying naked—his nakedness uncovered.
Whatever took place between Ham and Noah, why did Noah curse Ham’s son Canaan, when Canaan is nowhere mentioned as having done anything? The Bible does not specifically answer this question. Ham was Noah’s youngest son, and Canaan was probably Ham’s youngest son.
The “youngest son” who mistreated Noah (Genesis 9:24) seems to be a reference to Ham, but another option is that it refers to Canaan, Noah’s youngest grandson. Calling a grandson a “son” is not uncommon in Scripture (Ezra 5:1 and Zechariah 1:1). This would mean that Canaan was somehow involved in the sordid incident, and that is why Noah specifically mentions him in the curse (verse 25). Ham saw his father’s condition and did nothing about it except to tell his brothers. Reading between the lines, we assume that Ham’s son did more than see but participated somehow in his grandfather’s degradation.