This thesis investigates the occurrence of partnership conflicts and changes in relational dynamics after the birth of the first child. The main questions focus on personal and cooperative changes during the transition to parenthood. With regard to conflict situations, the participant's gender categories, competences, solution strategies and actions are considered. A qualitative investigation consisting of interviews with eight couples completes the discussion of relevant theoretical approaches and state of the art literature. The main results show that all actors adapt to the new situation ? i.e. the birth of the first child ? by modifying their role perception as parent, their intimate relationship, their employment and their division of housework. In order to counteract conflicts at the interfaces of family, parenthood, household and career, the interviewees adopt various solution strategies like conversation, discussion, agreement, legitimation, relativisation, and personal pull-out. Certain aspects proof to be consistently relevant, e.g. subjective definitions, desires and attitudes, personal competences and actions, collective experiences and knowledge about positive and/or negative communication. The empirical results confirm the chosen theoretical approach and allow a deeper understanding of personal and cooperative developments during the transition to parenthood.