Young adult fiction (YA) is a category of fiction written for readers from 12 to 18 years of age. The term YA first began to be used in the 1960s, to describe novels that realistically portrayed the lives of contemporary adolescents. While the genre is targeted at adolescents, a 2012 study found that 55% of YA readers were adults.The characters and subject matter has particular relevance to the lives of teenagers. The YA category includes most of the genres found in adult fiction, with themes that include friendship, sexuality, drugs and alcohol, and sexual and gender identity. Stories that focus on the challenges of youth may be categorized as problem novels or coming-of-age novels. The designation of young adult fiction was originally developed by librarians to help teenagers make the transition between children's and adult literature. Source: Wikipedia (en)