Hen Semi (変ゼミ, Hen Zemi), also known as Abnormal Physiology Seminar, is a Japanese comedy manga series written and illustrated by TAGRO and is a remake of TAGRO's earlier manga series, Hentai Seiri Seminar. Hen Semi has been serialized in Kodansha's Morning 2 manga magazine since 2006. It has been adapted into an original video animation in 2010, as well as an anime television series in 2011.
Nanako Matsutaka is an innocent university student who is participating in a sexual perversion seminar led by the deviant professor Kenji Meshiya. She desperately tries to keep her morals as well as her sanity while amidst the strange group of students in the study group.