5:32 begat Shem. Shem, Ham and Japheth were not triplets. Japheth is later called “the elder” (Genesis 10:21) and Ham the “younger son” (Genesis 9:24). However, Noah was five hundred years old before any of these sons–who were the ones who chose to go with him on the ark–were born. Evidently all of Noah’s older “sons and daughters” had followed the ungodliness of their aunts and uncles and of the world in general, and thus eventually perished in the Flood.