In many jurisdictions registered partnerships were introduced either as a functional equivalent to marriage for same-sex couples or as an alternative to marriage open to all couples. As marriage is opened up to same-sex couples in an increasing number of jurisdictions, this raises the question of what the future of registered partnerships should be. Is there a function or indeed a need for another form of formalised adult relationship besides marriage?In this book, leading family law experts from 15 European and non-European countries present and explain the history and function of registered partnerships in their own family law systems as well as the role registered partnerships play under the ECHR and under EU law. In the concluding chapters the different approaches are analysed and compared. This book provides the basis for an informed discussion on the way forward for jurisdictions reviewing the recognition of adult relationships in general and registered partnership regimes in particular.