If two twin sisters who are both 18 years old and they both want to marry eachother I think legally they should be allowed to do it because what they’re doing isn’t hurting anybody.
If a brother and a sister who are both consenting adults and they both want to marry eachother I think legally they should be allow to do it as long as the brother gets a vasectomy so that they do not have any kids together. Because what they’re doing isn’t hurting anybody.
I agree that incest is weird and gross which is why I personally would never do that but I don’t think that it’s morally wrong as long its between siblings that are both consenting adults and they do not have any kids together because what they’re doing is completely harmless and isn’t hurting anybody. So they deserve to have the right the right to marry eachother if they want to just like everyone else that isn’t related to their spouse.
On the one hand, the first reaction is “ew, that’s gross”. On the other hand, that’s also the reason people try to ban gay marriages.
Logically speaking, as long as there’s no power imbalance and no chance of kids, I can’t think of a reason to ban incest. Especially for same sex couples.
In practice, incest is often done as a form of abuse of some kind. Too often for broad legal acceptance, in my opinion.
(Bio)logically when siblings breed their offspring come out genetically damaged most of the time. Nobody gets hurt when I sit in a dude’s lap.