The term "shotacon" is a Japanese bimoraic clipped compound of Shōtarō complex (正太郎コンプレックス Shōtarō konpurekkusu), a reference to the young male character Shōtarō (正太郎) from Tetsujin 28-go. In the anime and manga series, Shōtarō is a bold, self-assertive detective who frequently outwits his adversaries and helps to solve cases. Throughout the series, Shōtarō develops close friends within the world. His bishōnen cuteness embodied and formed the term "shotacon", putting a name to an old sexual subculture.
Where the shotacon concept developed is hard to pinpoint, but some of its earliest roots are in reader responses to detective series written by Edogawa Rampo. In his works, a character named Yoshio Kobayashi of "Shōnentanteidan" (Junior Detective Group, similar to the Baker Street Irregulars of Sherlock Holmes) forms a deep dependency with adult protagonist Kogoro Akechi. Kobayashi, a beautiful teenager, constantly concerns himself with Kogoro's cases and well-being, and for a time moves in with the unmarried man. This nonsexual but intimate adult-boy relationship in part inspired the evolution of the shotacon community.
Tamaki Saitō describes the modern shotacon dōjinshi community as having largely formed in the early 1980s and having a roughly even split between males and females. Saitō suggests that shotacon was originally an offshoot of yaoi, but when adopted by male readers became influenced by lolicon; thus, he claims "shota texts by female yaoi authors are structurally identical to yaoi texts, while shota by male otaku clearly position these little boys as young girls with penises".