Re: Marrying your adopted sister !!?!!??
I think the biological relationship is more important than how they were raised. I can tell you what would be weird, a brother and sister sharing the same dad, not knowing they’re related, getting married to each other. Them being raised as siblings or not has no bearing on the weirdness of the situation.
That said, I think the state shouldn’t interfere with such couples(biological siblings) as long as one of them is sterile or they’re a same sex couple. It might seem weird but who are we to judge if they’re not ruining anyone’s life.