Yaoi derives from two sources; in the early 1970s, shōjo manga magazines published tanbi (aesthetic) stories, also known as shōnen ai (boy love), featuring platonic relationships between young boys.
The other influence began in the dōjinshi (fan fiction) markets of Japan in the late 1970s as yaoi, a sexualized parody of popular shōnen manga and anime stories.
Although the yaoi genre is also called Boys' Love (commonly abbreviated as BL), the characters may be of any age above puberty, including adults.
Works featuring prepubescent boys are labelled shotacon and seen as a distinct genre.
The word was originally used to describe an author's distinctive style, for example, the styles of Yukio Mishima and Jun'ichirō Tanizaki.
Akiko Mizoguchi describes its application to male-male stories as "misleading", but notes "it was the most commonly used term in the early 1990s." and were replete with "philosophical and abstract musings".
In the late 1970s, shōjo magazines devoted to the new genre began to appear; and, in the 1990s, the term boys' love or BL was invented for the genre, which replaced earlier terms such as tanbi, shōnen ai and juné in Japanese usage.
In Japan, the term yaoi continues to refer mainly to parody dōjinshi; among Western fans, however, yaoi is used as a generic term for female-oriented manga, anime, dating sims, novels and fan fiction works featuring idealized gay male relationships.
The genre currently known as Boy's Love, BL, or yaoi derives from two sources.
Female authors writing for shōjo (girl's) manga magazines in the early 1970s published stories featuring platonic relationships between young boys, which were known as tanbi (aesthetic) or shōnen ai (boy love).
In the late 1970s going into the 1980s, women and girls in the dōjinshi (fan fiction) markets of Japan started to produce sexualized parodies of popular shōnen (boy's) anime and manga stories in which the male characters were recast as gay lovers.
The term shōnen-ai (boy love) originally connoted ephebophilia or pederasty in Japan, but from the early 1970s to the late 1980s, was used to describe a new genre of shōjo manga, primarily produced by the Year 24 Group of women authors, about beautiful boys in love.
Characteristics of shōnen-ai include exoticism, often taking place in Europe, Jeffrey Angles particularly notes Moto Hagio's The Heart of Thomas (1974) and Keiko Takemiya's Kaze to Ki no Uta (1976–1984) as being groundbreaking, noting their portrayal of intense friendship between males, including jealousy and desire.