In English, shoujo-ai is a genre of lesbian fiction. Any manga or anime focused on the romantic relationship of a girl with another girl falls in this genre. In Japanese, the word means "pedophilia" instead.
Its gay counterpart is shounen-ai.
Right: Nanami Touko 七海燈子
Anime: Yagate Kimi ni Naru やがて君になる (Episode 1, Stitch, Censored)