The Fetish for young females or someone with the fetish for young females.
He is a rorikon!
Rorikon means pedophile (Which is also known as "lolicon".).
The word "Rorikon" isn't English, it's Japanese, this is how it looks written in Japanese : ロリコン (You won't be able to see it, unless you have installed the Asian language pack)
If you don't know what a pedophile is : "Pedophile persons can feel an attraction to children of a different sex, to children of the same sex, or both."
Just a friendly tip, stay away from child porn.
Person A : I don't know what's wrong with him, but I keep on seeing him flirting with young girls.
Person B : Maybe because he is a rorikon?
Person A : ...A what?