two lesbian twin sisters who are both 25 years old who are in an incestuous relationship with each other is morally okay in my opinion because what they’re doing is completely harmless.
Just because society thinks it’s gross and weird that doesn’t mean that it’s morally wrong.
So how is straight incest different? If lesbian incest is harmless, how is straight incest not?
Straight incest between a brother and a sister is only morally okay if they’re both are consenting adults and the brother gets a vasectomy so that they can’t have any kids together.