
That’s literally not true lmao and that’s ignorant of you to say. It’s because tropes like this that step siblings and adopted children feel invalidated because they aren’t blood related. Many people see their adopted and step siblings as their actual sibling because they ARE their sibling. You don’t need to be blood related to still have a familial relationship. This trope literally fetishizes adopted and step sibling relationships and its inherently harmful especially since these manhwas are marketed towards impressionable teens and children.

You are so right - i wish writers hab basic biology culture : here is food for your thoughts - it is said that from vegetal to animal, nature worked hard to prevent breeding in the same family. - aven trees are made tco crossbreed, and in humans there’s something called « westermack effects-
It’s contemporary and contradictory to Freud : it establishes that people raised together have a strong aversion to sexual intimacy - it’s true for all family members, whether there are biologically connected or not - so no, little children do not have this kind of desire for their parents (there’s no œdipe complexe!), and neither do siblings or step siblings raised together in small age grow this kind of drive
In fact it comes from observing tribes or culture which made arrangements to take in small kids in for future mariage, with the idea the kid would know each other better - but reality proved they make miserable couple, with less or no kids and more divorces - they can’t change the way of their brother /sister relationship, and it’s not fit for « reproduction «
Step kids raised together don’t wish to marry - that’s been proven more than a century ago !
I’m so tired of the step sibling likes the other step sibling trope. Atp it’s so overdown and is just insulting to real step siblings and invalidates adopted children. “Oh it’s okay for them to like each other because they aren’t blood related.” They’re still siblings and are family. Just make one of them a childhood friend or something.