That’s a good question. Two verses suggest this might be the case.
In Genesis 5:32 we read that Noah lived 500 years and begat Shem, Ham and Japheth. Then again we read in Genesis 11:26 that Terah lived 70 years and begat Abram (Abraham) , Nahor and Haran. We might want to assume that this just means they were born after Noah turned 500 or Terah turned 70. But in every other case the verse reads like this: And “the father” lived “x” years and begat “the eldest son” and after “the father” begat the “eldest son” he lived “y” years and begat sons and daughters.
So it is unusual to list three sons by name and not just one. Could this be because they were triplets and the first to be born is known as the eldest? Or might there be another reason?
We get a clue from Noah’s sons. Here’s what else we learn from Genesis. Shem begat Arpachshad when he was 100 and Arpachshad was born two years after the flood (Genesis 11:10). We know that Noah was 600 years old at the start of the flood (Genesis 7:6). So what do we get from this? If Shem was born when Noah was 500 he would have been been 100 the year of the flood but he isn’t 100 until two years later when Arpachshad is born That means Shem was born when Noah was 502.
This tells us, at least in the case of Noah’s sons, that they aren’t triplets. There must be another reason for listing the names of certain sons. Generally the sons are listed to establish the lineage of the prophets. The only time the names of other sons (or daughters) are listed by name is because they have a major role to play in Biblical lineage and the family of man. We know for sure that applies to Noah and his three sons since all the nations of the world are descended from those three.
Does that same reasoning apply to the sons of Terah? What about Nahor? His lineage is very important. Nahor is the grandfather of Rebecca, the wife of Isaac. And of course Haran and his descendants are also key members of Abraham and his family.
Nahor married his niece Milcah, the daughter of his brother Haran and the sister of his nephew Lot. Nahor lived in the land of his birth on the east of the river Euphrates at Haran. He was the father of Bethuel and grandfather of Laban and Rebecca; Rebecca became the wife of Isaac son of Abraham. Nahor’s great-granddaughters through Laban, Rebecca’s nieces Rachel and Leah, became the wives of Jacob son of Isaac.
In addition the birth of triplets is remarkable even in this day and age. The Bible states unequivocally that Jacob and Esau were twins. It seems odd that it isn’t explicitly stated that the sons of Terah were triplets, if they were, since it would have been a truly unusual event.
Were there triplets in the Bible? We know Noah’s sons weren’t. We can’t say for certain about Terah’s but probably not.