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 fictional boys 16 or younger, or who is attracted to fictional boys who have the appearance of a character who is 16 or younger. See also: Shotacon
The girl version is called Lolicon.