Who was Noah's youngest son?
In the genealogies, the Bible consistently lists the male children in the order of their birth. In Genesis 5:32 we find the order of birth for Noah’s children to be as follows:
And Noah was five hundred years old, and Noah became the father of Shem, Ham, and Japheth. (NASB) Genesis 5:32
Therefore, it seems reasonable to conclude that Japheth was the youngest child. Genesis 9:2 gives us his sons.
The sons of Japheth were Gomer and Magog and Madai and Javan and Tubal and Meshech and Tiras. (NASB) Genesis 9:2
It is wonderful that God has given us the genealogies. It was a way of understanding history and eventually the right of Jesus Christ to sit on the throne of King David. Praise the Lord!