I’m curious to know how birth defects were treated by people before modern day or before people had a better understanding of genetics and how physical abnormalities or conditions occur.
This is a very broad answer.
For Medieval Europe:
For the Classical Mediterranean:
I might also throw in an answer of my own on disability and birth defects in ancient and early medieval China, especially some of the fascinating perceived association between physical defects like extra fingers and wisdom or talent in Zhou times and its transition to how Sima Zhong of Jin was treated during his reign. If I have time this week, hopefully.