My only objection is when it comes to children being born from incest because of the higher risk of genetic diseases.
But that’s still not a 100% consistent argument and it leans into another morally complex topic: eugenics.
Because, if you argue that way, you’d have to clarify your stance towards people with genetic diseases/disabilities in general.
And if you follow the logic, we would also have to shun/abolish sexual relations between people with genetic disease or who carry the respective alleles, so that their offspring have a higher chance of inheriting a disease (in some cases way higher than with random siblings).
It might be the root cause, why there seem to be marriage rules in most human societies, that exclude intermarrying of siblings (especially considering that the risks increase drastically if you keep procreating that way for generations), but the current taboo is not entirely rational and seems more based on cultural tradition than current understanding.
But that’s still not a 100% consistent argument and it leans into another morally complex topic: eugenics.
Because, if you argue that way, you’d have to clarify your stance towards people with genetic diseases/disabilities in general.
And if you follow the logic, we would also have to shun/abolish sexual relations between people with genetic disease or who carry the respective alleles, so that their offspring have a higher chance of inheriting a disease (in some cases way higher than with random siblings).
It might be the root cause, why there seem to be marriage rules in most human societies, that exclude intermarrying of siblings (especially considering that the risks increase drastically if you keep procreating that way for generations), but the current taboo is not entirely rational and seems more based on cultural tradition than current understanding.