I do wonder about if the incest taboo is grounded of scientific fact or superstition.
Charles Darwin as an individual pushed the narrative that mankind came from apes rather than a divine origin, while this was good at getting us away from Christianity it also suggested we are monkeys without a divine spark. If he was a jewish agent then his attacks on incest could have been done to undermine the idea of racial purity. He also suggested mixed spices animals were stronger due to what he called “hybrid vigor” a blatant attack on racial purity.
It is said the ancient royalty/nobility practiced marriages within their family in order to maintain racial purity within the lands they conquered rather then marry the natives. Purity came from similarity rather than genetic differences. This could just be slander for by the jews but it could be true.
The Spanish kings are also brought up as an example of how that could go wrong, however if you know anything about Spanish history you know the nobility was full of jews and Muslim Africans that converted to keep their lands so this could have been the product of cross breeding that made them all deformed.
When it comes to genetics modern science has actually found that genes make proteins, building blocks of the body but they impact how those proteins get used. Spiritual power may also be a recessive trait, recessive traits may actually be positive things we want to develop rather then avoid.