Parent-child incest is a problem in the nuclear family because of the authority issues. I note in passing, however, that the nuclear family itself is absolutely not in the child's best interest in the first place: it takes a village to raise a child.

Another risk that nobody mentioned is that of the child taking advantage of the parent to get expensive gifts, get out of chores, etc. Some children think that way. The flipside to the idea of the authority structure undermining the sexual relationship is that of the sexual relationship undermining the authority structure!

Student