We examined relationships between autistic traits in children, mothers, and fathers and gender nonconformity (GNC) in children using data from the Nurses’ Health Study II and the Growing Up Today Study 1. Autistic traits of mothers, fathers and children were measured using the Social Responsiveness Scale (SRS). GNC in children was measured using questions from the Recalled Childhood Gender Identity/Gender Role Questionnaire. In multivariable analyses increase in child’s SRS score was associated with increased odds (OR 1.35; p = 0.03) of being in a higher GNC category. Increase in maternal SRS score was also associated with increased odds (OR 1.46; p = 0.005) of the child being in a higher GNC category. Paternal SRS scores were not related to child’s GNC category.