The gendered division of housework and care has long been a key topic in family research. In this qualitative study, the aim is to deepen the knowledge of parents' division of labour by exploring how their division of housework and care changes over time. We are specifically interested in how the cognitive labour emerges and develops as couples transition into parenthood and the following years: (1) How is the division of labour among couples modified, maintained, and/or challenged during the transition to parenthood, and as their children go from early childhood to school-age? and (2) how does cognitive labour, and the different aspects of such labour, emerge over time among studied parental couples? Drawing on theories of gender, care and cognitive labour, a key finding concerns the gradual emergence of the female planning responsibility, a central aspect of cognitive labour. Although the parents wanted to share the care and housework equally, it was still the mothers who mainly carried this invisible responsibility. The findings thus suggest that even when couples are reflecting and trying actively to avoid falling into a traditional gendered division, the new parenthood puts these norms and values to a test.