What's given raises a gamut of questions. Main among them is, Who's the reader surrogate? The relational standing the other characters have to a reader surrogate flies or falls according to the reader surrogate's expressed commentary about them and therefore what the commentary says about the reader surrogate. Pro age disparity relationships or anti, anti or pro gay relationships, and so on, whatever the central message of the expressed commentary is and the central theme go toward the point of the novel for Unity's sake. Otherwise, an And Plot and/or Kitchen Sink Plot might be the consequence.
An And Plot is where something happens in the beginning, and something happens in the middle, and something happens in the ending, and to no coherent meaningful end. A Kitchen Sink Plot is where anything and everything imaginable happens and in no particular structural organization.
Another primary question, What's the main dramatic complication as it relates to the outcome? While not an absolute, a reader surrogate's standing to the main dramatic complication ideally has him or her or it in a main and proactive contention role with the complication.
I could see most anything goes as long as it's age appropriate genre. Young adults contend with the traumas of violence and rape, and countercultural relationships' many challenges; however, young adults have a narrower scope of life experience to draw on and therefore a narrower world view, fewer viewpoints from which to process the influences of the more extreme sides of life. Early adults come into contention with more extreme viewpoints, and older adults still more extreme.
A final primary question, What's the rating? PG? PG-14? R? MA? X? XX? XXX? Graphically depicted rape falls into the latter ratings, same with graphic violence. Relationship age disparity can be anything higher than G. R won't raise too many objections for young adult genres.
J.D. Salinger's Catcher in the Rye falls into the R or MA ratings. Robert Cormier's The Chocolate War falls firmly in the PG-14 rating, but nonetheless is regularly challenged by moral authorities. S.E. Hinton's The Outsiders shouldn't be an R or an MA but it's treated that way by moral authorities. Cynthia Voight's Homecoming, again, shouldn't be an R or MA but moral authorities treat it that way.
Motifs of premarital or extramarital sex or graphic sex of any kind, homosexuality, graphic violence, vulgar language, single parent households, tobacco or drug or alcohol use, mental dysfunctions, criminal or rebellious conduct, and so on affect rating scale. Although there's no formal rating system for literature anymore, there's a moral authority agenda that runs one underground by a word of mouth grapevine that drives book banning in libraries and schools.
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