A father and mother who repeatedly remarry their stepchildren. Children raised in such an environment may be brothers or sisters, but they are not related by blood. Every day we live together as a family in a literally improvised state. Because the moral values of their parents have collapsed, their children are similarly detached from the world. Therefore, this situation can be said to be abnormal as the target of sexual desire is directed towards the family at hand. But for this family, it's normal.