The question of what kinds of constellations of personal relationships
are recognised as family life by Member States of the Council of Europe
has been under intense litigation in recent years in the European Court
of Human Rights (ECtHR). This article examines the ECtHR as an arena
where different realms of knowledge come together and produce
interpretations of human rights norms according to historically
contingent and sometimes conflicting attempts to produce decisions that
reflect ‘human rights rationality’. By analysing five judgments from the
2000s and 2010s, this article focuses on State-argued cultural
understandings of limits of acceptable forms of marriage and family
life. The cases concern marriage between former in-laws, sexual
relations between genetically related siblings and understandings of
maternity in contexts of egg donation and surrogacy. The judgments offer
examples of legal arguments and extra-legal knowledge that have been
applied by States and the ECtHR itself when arguing for, or against,
giving particular understandings of family life legal protection in
interpreting the European Convention on Human.