This thesis investigates the construction of parenthood in single-parent adoptive families. A qualitative research was carried out, in which nine women and three men aged between 38 and 61 years old from the average socio economic strata of four Brazilian cities that adopted children more than two years ago, were interviewed. The results were analyzed according to the content analysis method in its categorical aspect. From this analysis, nine categories emerged: in additionto infertility, motivations for the profile, deep emotional motivations, child s initial reactions, feelings of loss and grief of the child, articulation of two stories, interracial issues, narratives of adoptive affiliation, and transmission of the storyof origins. The results and their analyzes are presented in four articles. In the first,motivations in the transition to single adoptive parenthood are investigated. The data indicate that the absence of a partner or the lack of interest in sharing parenting occupies a central place; the motivations for the child s profile are transformed through a process of reinterpreting the desire, but they are also influenced by the professionals involved in the adoption. The second article investigates the impacts of adoption on the construction of parenthood. It appears that the child s previous experiences and feelings of loss and mourning constitute the main impacts. In the third article, generational transmission in the construction of parenthood is investigated. The identification and affective processes are in thefore ground and the personal history with the parents is articulated with that of the child as a means for them to elaborate their adoptive history. The fourth article investigates the generational transmission of the child s story. It appears that children need to reconcile their current history with their origins; parents musttake into account the child s curiosity and their ability to absorb information, trust the bond established with their children and redefine traumatic truths in joint psychic work. It is concluded that the construction of adoptive parenthood insingle-parent families was marked by motivations that differ from those of couples, characterized by the configuration of the desire for parenthood at a later stage of life, with the predominance of identification processes and the desire to transmit. The motivations for the child s profile are renewed in a process of reinterpreting the desire. The child s initial reactions emerged as the main impacts of adoption, perceived differently between male and female adopters, opening a discussion about the social context that places child well-being centered on women. Additionally, the child s feelings of loss and grief challenge parents todeal with their own feelings and the ambiguities of adoption, and to develop openness regarding their children s feelings. Intergenerational transmission in the researched group is marked by ruptures with the two-parent family model, with intra-family racial homogeneity and with the child s biological family. Individual experiences with parents gain intensity, not being influenced by a partner sparenting. The psychic work of enrolling the child in a genealogy is not affected by the hesitations typical of families with married couples. Interracial differences gain visibility in the case of families with a single genealogical line, observing the value of the family s network of ties in providing identification, favoring the construction of a positive racial identity. Interracial adoptions promote the experience of racial otherness, which transforms family values from one generation to the next, making parenting a privileged place for racial(re)socialization. The transmission of the story of origins proves to be highly challenging, but essential for the constitution of the adopted child s identity and for the consolidation of adoptive parenthood. Regarding younger children, the value of different types of narratives and non-verbal communication is observed.