This study explored the effect of the gendered structure of siblings in intact and non-intact families, on family relations, social support, perceived control, and psychological distress in a sample of 708 young adults (294 males and 414 females) aged between 18 - 21 years. Of the sample 96 were singletons, 208 had both a brother and sister, 206 had a brother and no sister, and 198 had a sister and no brother. While the results show that both the gender of the participants and the gender of the sibling seem to impact on distress and its mediators; the more important factor is the gender of siblings. In essence the presence of a female sibling is associated with more perceived support, control and optimism, and with lower pessimism and psychological distress. The presence of a female is also associated with better family relations overall and it is suggested that the main mechanism for this positive impact of female siblings is through the lowered conflict and increased expressiveness and cohesion experienced in female versus male dominated sibling groups.