Therefore, allow one or more ParentPages to be selected from the child's BackLinks. When a page is first created, use the page it was created from as its initial parent. Display a page's parents in the title bar for the benefit of the reader.
Keeping the ParentPages a subset of the BackLinks prevents a child displaying parents that have disowned it. A tool to allow the designation of children from a pages' ForwardLinks? would be handy.
But, providing sensible PeerReview of changes to ParentPages may be impossible on many wikis without substantial changes to their RecentChanges design. Also, a page cannot be categorized without editing the category page, unlike simple ReverseIndex-based categories.
(Idea originally described on ZWiki:WikiStructuringIdeas)