This paper estimates peer effects both from older to younger siblings and from parents to children in academic fields of study. Our setting is secondary school in Sweden, where admissions to oversubscribed fields is determined based on a student's GPA. Using an RD design, we find strong spillovers in field choices that depend on the gender mix of siblings and whether the field is gender conforming. There are also large intergenerational effects from fathers and mothers to sons, except in female-dominated fields, but little effect for daughters. These spillovers have long-term consequences for occupational segregation and wage gaps by gender.