This is an exploratory study that examines the publication and use of sex education books for youth and considers their values and applicability to sex education for youth in the future. In-depth interviews were conducted with book editors, sex education experts, and public librarians—those who play important roles in children and young adults’ reading of sex education books—and analyzed. According to the research participants, parents and caregivers often rely on sex education books when they find it hard to deliver sex education to their children on their own. Sex education books are also often used by sex education experts in their classes. The research participants said many sex education books that were published in South Korea only focus on ‘the body education,’ which deals with body changes during puberty. Gender inequality is another subject that needs to be changed. The research participants agreed that a sex education book should not just be a simple medium that delivers fragments of knowledge on sexuality but a broader learning playground where children and young adults can learn independent perspectives on sexuality based on comprehensive views on life. This study suggests a guideline for sexuality education books, which will be useful for library collection development.