Did you know adopted childrens have no responsibility towards their biological parents? because you may be surprised to know some people do think that.
It is often said “Blood is thicker than Water” as a way to reffer to the importance Family Unity. Likewise, “The apple doesn’t fall far from the tree” often reffers to childrens ending up like their parents. The idea being that the blood connection between individuals means one has a responsibility towards those they share a biological connection with or that they are somehow destined to be like them because they have the same blood.
Oddly enough, those words, when applied to adopted childrens, are rarely used to reffer to their adoptive parents, but rather to their biological, “real” parents.