Yaoi (やおい) is a popular term for fictional media that focuses on homoerotic or homoromantic male relationships, yet is generally created by and for females. Originally referring to a specific type of dōjinshi (self-published works) parody of mainstream anime and manga works, yaoi came to be used as a generic term for female-oriented manga, anime, dating sims, novels and dōjinshi featuring homosexual male relationships.
** Spoiler Alert!!! click to hide or show**
In Japan, the term has largely been replaced by the rubric Boys' Love (ボーイズラブ ,Bōizu Rabu?), which subsumes both parodies and original works, and commercial as well as dōjinshi works. Although the genre is called Boys' Love (commonly abbreviated as "BL"), the males featured are pubescent or older. Works featuring prepubescent boys are labeled shotacon, and seen as a distinct genre. Yaoi (as it continues to be known among English-speaking fans) has spread beyond Japan: both translated and original yaoi is now available in many countries and languages.
Yaoi began in the dōjinshi markets of Japan in the late 1970s/early 1980s as an outgrowth of shōnen-ai (also known as "Juné" or "tanbi"), but whereas shōnen-ai (both commercial and dōjinshi) were original works, yaoi were parodies of popular "straight" shōnen anime and manga, such as Captain Tsubasa and Saint Seiya. BL creators and fans are careful to distinguish the genre from “gay manga,” which are created by and for gay men. However, some male manga creators have produced BL works.
The main characters in BL usually conform to the formula of the seme (aggressor) who pursues the uke (the target).