incest is bad and wrong because of power dynamics and grooming done to people. reproductive incest is also bad because of the genetics stuff but incest taboo predates that and historical people had a bunch of weird ideas about bloodlines which gave us the hapsburg chin.
the vibe against incest comes from the westermarck effect and social norms, but e.g. first cousin pairings are iirc genetically safe if you don't do several generations of them and such marriages are legal in a lot of places.
additionally, once in a while siblings separated at birth accidentally end up in incestuous relationships without knowing. there was a case in germany maybe 10-15 years ago and i've forgotten most of the details but i think they got sterilized after finding out and were allowed to stay together since there was no power imbalance and no risk of genetic whatever.
![[CW: bestiality] Professional "moral philosopher" ponders whether it's OK to sexually assault animals, featuring AI art](https://hexbear.net/pictrs/image/f26b2dce-7254-4537-acd1-5de623b591e0.png){kind=link}
incest is bad and wrong because of power dynamics and grooming done to people. reproductive incest is also bad because of the genetics stuff but incest taboo predates that and historical people had a bunch of weird ideas about bloodlines which gave us the hapsburg chin.
the vibe against incest comes from the westermarck effect and social norms, but e.g. first cousin pairings are iirc genetically safe if you don't do several generations of them and such marriages are legal in a lot of places.
additionally, once in a while siblings separated at birth accidentally end up in incestuous relationships without knowing. there was a case in germany maybe 10-15 years ago and i've forgotten most of the details but i think they got sterilized after finding out and were allowed to stay together since there was no power imbalance and no risk of genetic whatever.