
This has sort of piqued my interest a bit because incest did happen sometimes throughout history (especially like royal families and such) but my understanding is that it was still pretty taboo and most religious institutions banned it. Like the book of Leviticus in the Old Testament, written thousands of years ago, strictly forbade marriage between close family members. Clearly they didn’t understand the genetic reasons for why incest was harmful, so it must just be some kind of evolved
I think it’s bc of how those relationships usually spawn out of a power imbalance or how it causes problems in the family and the community. Especially bc incest wasn’t usually siblings—it was parents/cousins/aunts or uncles. And they might’ve not understood the science but they def saw the effects.