The birth of a child may re-orientate the relations between adult children and their parents; however, the previous studies on the topic are both scarce and methodologically limited. The current study investigates whether younger adults' entry into parenthood (i.e., the birth of the first child) is associated with increased contact frequency, emotional closeness, intimacy and conflict with their own parents. The participants are from the German Panel Analysis of Intimate Relationships and Family Dynamics, which is a prospective survey of younger adults with six annual follow-up waves between 2009 and 2014 (n = 17,662 person-observations from 4821 persons). Within-person regression with a focus on each individual's variation over time was used to detect changes in intergenerational relations. The contact frequency between daughters and mothers increased after the arrival of their first child. In contrast, the emotional closeness and intimacy between sons and mothers decreased after the birth of their first child. The results are discussed with reference to gender-based differences in intergenerational relations.