The Old Testament has a couple of references to it. A number of ancient cultures around the world practiced child sacrifice. Search Wikipedia for that lest term. This site won’t let me post a link.
There were three monkeys way up high in a tree. Although they were very high up, they were, in fact, on the lowest branch. After a while, the first monkey fell out of the tree. Why? Simple: he died. Some time after that happened, the second monkey fell out of the tree. Why? Simple: he died. A few minutes later, the third monkey fell out of the tree. Why? Simple: peer pressure!
Argh! I have never liked “tradition” as the answer to why people do something. My response is: “It used to be traditional to kill the first-born; you were the first-born, right?” To date, only two people to whom I’ve said that have gotten the joke.
The Bible isn’t the only source I provided.