Yoshino, the other protagonist, is tall and masculine. At the beginning of Hourou Musuko, she is a fifth grader in Shuuichi's class. Known as Takatsuki-kun by her classmates, she expresses a strong desire to be male. Despite her mother's insistence on buying traditionally feminine clothes like skirts or dresses for her, Yoshino usually avoids wearing them. Shortly after befriending Shuuichi, Yoshino cuts her hair very short, giving her a boyish appearance, especially when dressed in a male school uniform. Like Shuuichi, Yoshino becomes increasingly worried and resentful about her changing body due to puberty. She even buys a garment to flatten her chest so that she doesn't have to wear a bra.
While Yoshino wishes she could dress and act like a boy all the time, she refrains from drawing attention to herself by avoiding overt actions such as attending junior high in a male uniform. However, she occasionally dresses in a male school uniform and visits neighboring cities presenting as male. During one such occasion, she enjoys being hit on by an older woman. Yoshino prefers to look "cool," wearing clothes that make her appear less feminine. When teased by others, Yoshino can become emotional and sometimes even violent. After entering junior high, Yoshino takes up an interest in basketball and joins the girls' basketball club with Chizuru Sarashina. In junior high, she grows her hair out following a comment from Saori but later cuts it short again.
Her family includes her father, mother, older brother, and older sister. Towards the end of the manga, Yoshino decides to take up modeling and lets her hair grow out again. She stops wanting to be a boy and feels some guilt towards Shuuichi, who still identifies as a girl. When they meet again after a period of no contact, Yoshino finds herself attracted to Shuuichi, but nothing comes of it because Shuuichi is already in a relationship with Anna.
