I see,
You all have a carefree point of view huh?
Or it was just me who was too strict here...haha.
But, yeah, I got the point!
For this Topic, LEWD yes, children no
Well, you can not see this as black and white. It’s also not some fantasy kink like tentacles, but something more common irl than you’d think.
Separate two siblings at birth and don’t let them know they are adopted. Maybe they will fall in love as adults and want to marry, but BOOM. They are siblings and can’t. Only because of their blood.
Take another example childhood friends since they were small. Totally legit and a trope in romance. Ai, sweet, sweet, childhood sweethearts.
Step siblings, possible by law cause no genetic problems. But it feels immoral because they are still “siblings” yet they could be also described as childhood friends. They knew each other their whole life like real siblings.
Now take same sex incest. They can’t have offsprings so the immoral feeling is solely because the stereotype of how this family relationship should be. This is what we grew up with, this is how siblings/parent-child relationship should be, this is how society stipulated it.
And then we go back to medieval times and older societies where genetic problems were still unknown… Incest is more a head thing imo.