Kegareboshi Animation Info

The story takes place in a world where homosexuality is the norm, and heterosexuality is seen as a genetic abnormality known as "Kegare" (stigma). The main character, Kazuya Fuyou, is a young man who possesses the rare "normal" gene and becomes the target of attention and desire from those who are attracted to him.

I believe you're referring to "Kegareboshi"! kegareboshi animation

Kegareboshi, also known as "Stigma" or "" in Japanese, is a Japanese anime television series created by Kazuya Minekura. The series premiered in 2004 and consists of 26 episodes. The story takes place in a world where