This thesis aimed to investigate transformations in the exercise of paternity, from the perspective of the father. A qualitative research was carried out in which 15 primiparous parents were interviewed. The results were analyzed according to the content analysis method in its categorical aspect. From the material evaluation, five categories of analysis emerged: conception of paternity, male participation in pregnancy and childbirth, paternal care practices, transition to parenting, and postpartum and paternity leave. For the purpose of presenting the development of the investigation, the thesis was divided into five articles. In the first, the conception of paternity in the gestational period and in the first months of the baby s life for parents was investigated. The results revealed that the experiences lived by man in the family of origin influence the conception of fatherhood, especially the relationship established with the father himself is highlighted in this process. In the second, the father s participation during pregnancy, childbirth and postpartum was studied, and it was found that, at present, the father is more present in the clinical gestational context. Its presence in these environments has been recognized as beneficial to the mother-father-son triad. In the third article, the care practices carried out by the father in the baby s first year of life were investigated, from a male perspective, and it was observed that old conceptions that the mother is the main responsible for the children still remain. In the fourth, we analyzed the challenges experienced by the father in the transition to parenting after birth and in the first months of his son s life. The results suggested that, in view of the acquisition of the parental role, personal projects often need to be set aside, an aspect that can generate a decline in marital satisfaction. Finally, in the fifth article, the perception of parents about the expansion of paternity leave in Brazil was investigated. The data revealed that the current paternity leave, to which most Brazilian fathers are entitled, does not meet the needs of the family in the postpartum period. More broadly, it was concluded that the paternal identity is in transition, given that the traditional role of men as provider and more focused on the provision and security of the home, nowadays, merges with that of a more participative and engaged in child care.