Science versus Advocacy looms large in the debate on shared parenting in Germany as it touches upon a topic that is widely regarded to be one of the most contentious in present day policy making in Germany. The stakes are high and a broad debate would be desirable. Discourse theory spells out the conditions for a fruitful debate and provides a methodological framework for describing the characteristics of the German discourse on shared parenting. The paper analyses secondary sources of key participants in the debate against the backdrop of the presuppositions of an ideal communicative structure of rationality, reflexion, inclusiveness, and truthfulness. Where these communicative structures are missing to a large extent policy makers, legal professionals and practitioners in family policy will be shielded from the 'best information available' and advocacy will prevail over science.