["JCMS: Journal of Common Market Studies, EarlyView. ", "\nAbstract\nThis article analyses the European Union (EU) Proposal on the mutual recognition of parenthood as a case to examine the dynamics of European integration in highly politicised domains such as family law, same‐sex parenthood and surrogacy, where the Union has limited formal competences. Drawing on a framing analysis of institutional documents, parliamentary debates, Council negotiations and interviews, it shows how children's rights were mobilised as a central frame in the legislative process. The article contributes to European integration scholarship by demonstrating how integration in sensitive civil‐law domains proceeds through the strategic mobilisation of rights‐based frames under conditions of strong legal and political constraints. It argues that, in this context, Member States operate not only as legal gatekeepers but also as custodians of domestic political equilibria within the integration process. The findings have broader implications for EU policy domains characterised by moral contestation and constrained competences, including reproductive rights, bioethics and education policy."]