Shotacon

Shotacon, sometimes shortened to shota (ショタ), is a Japanese slang portmanteau of the phrase Shōtarō complex (正太郎コンプレックス). A Shotacon is described as a person who is attracted to young, or young in appearance, fictional boys. See also: Shotacon

An illustration of an older female character attracted to a shota, characteristic of shotacon

The girl version is called Lolicon.