The Kurokami siblings are all geniuses. Oldest child Maguro realizes his analytic brilliance in the process of trying to help one of his two beloved younger sisters. Kujira, the middle child and eldest sister, willingly lives a deprived, isolated life of nothing but studying and experimentation in order to become an expert on biology, whereas youngest sibling, Medaka, is an all-around prodigy who can excel at essentially everything she sees.
From the anime series Medaka Box
Sister/Brother Complex 