Children with same-sex attracted parents develop well in terms of their health and wellbeing. There are many recognised factors that have an impact on child health, in general, including individual, family and wider social mediators. The aim of this study is to determine the impact of family structure and socio-demographic characteristics on child health and wellbeing in Australian same-sex parent families. METHODS: A cross-sectional survey of self-identified same-sex attracted parents from across Australia was used to collect information on child health and wellbeing between May and December 2012. Mixed-effects multiple linear regression models were used to identify associations between family structure/socio-demographic characteristics and child wellbeing. Child health outcomes were measured using the Child Health Questionnaire and the Strengths and Difficulties Questionnaire. RESULTS: In same-sex parent families, biological relationships, parental gender and parental education were not significantly associated with health and wellbeing. Parental income, rurality and stable parental relationships were associated with health and wellbeing, and living in a single-parent household was associated with poorer wellbeing. CONCLUSIONS: Stable dual parent families offer good outcomes for children with same-sex attracted parents. Family processes are most important. This study does not support the assertion that children require both male and female parents, nor that biological relationships are essential to health and wellbeing. This study provides scientific data from a cross-sectional Australian-based study to describe and understand health determinants for children in family contexts that comprise same-sex parent and all family contexts. It recommends equitable, stigma-free family support.