Many studies have highlighted the rise in unplanned pregnancies among young women in sub-Saharan Africa but few have focused on concomitant changes in young Africans’ aspirations with regard to sexuality and parenthood. On the basis of a study in Dakar, the capital city of Senegal, this article analyses the complexity of the individual and collective issues involved in responses to unintended pregnancy, showing that this notion speaks to a broader reflection on the question of contraception at the start of sexual life. The study is based on 74 life story interviews (49 with women, 25 with men) conducted between 2007 and 2008 in the framework of ECAF (Emergency Contraception in Africa), a research programme funded by the European Union. Data were collected by means of a qualitative biographical approach that provides an overall view of individuals’ residential, educational, occupational, affective and/or conjugal trajectories and contraceptive histories. Attitudes to motherhood are found to be structured by four dimensions: the social legitimacy of the relationship in which the pregnancy occurs, power relations among the various protagonists (individuals, couples, families and/or social circle), gender-based power relations, and increasingly precarious living conditions.