This article aimed to study the dynamic of same-sex parenting families formed by two women with children who have a biological bond with only one of them. We interviewed nine women -eight of them formed four couples and one was divorced -with ages ranging between 33 and 45 years, with children aging from 2 to 8 years, who were middle-class residents of the state of Rio de Janeiro, and had planned motherhood together using new reproductive technologies with semen from an anonymous donor. The following evaluation categories were discussed: kinship and affective relationship terminology; division of childcare related tasks; and the search for legitimacy. We observed that in the family settings studied, the children, in fact, identified both women as mothers, when both assume the role, demonstrating that the affective bond fulfilled its binding role.