It's just a Story about Peacocks

Kuji Yakurou is a high school teacher who was cheated on and dumped by his girlfriend because of his "lack of masculinity." Shouldn't the world be beyond gender stereotypes by now? He is in anguish, when Akano, a model, influencer, high achiever, and president of the Biology Club, asks him to be the advisor of the Biology Club. She then begins to explain how "masculinity" is necessary to attract females, using the flamboyant feathers of a peacock as an example of "biology"...! (Source: Kodansha, translated)