In this study, we analyze whether the gender of a student's siblings affects the choice of college major. A family with same-gender siblings may encourage academic choices that are less gender stereotyped. We use a unique dataset covering 30,000 Italian students who graduated from high school between 1985 and 2005 that allows us to identify siblings. We follow their academic careers from high school to college graduation. We find that mixed-gender siblings tend to choose college majors following a stronger genderstereotypical specialization: males have higher probability of choosing 'male dominated' majors such as Engineering and Economics. Same-gender siblings, on the other hand, have higher probability of making non-gender-stereotypical choices. This college major choice is not driven by the choice of high school academic curriculum, which appears to be mainly function of geographical proximity to schools.