In the teaching of the Catholic Church, the institution of marriage derives directly from God, for common good and for the good of spouses and children. Human authorities are called upon not to transform its characteristics and to avoid any attempts to distort them. However, the Church is today confronted with a changing understanding of the notion of ‘gender’ and with new considerations about the meaning of ‘marriage’ on behalf of parts of society and of political institutions. Based on an overview of the recent legislative and political proposals concerning family issues at the European level, this article aims to assess what model of family the Member States of the European Union are developing, and how the traditional concept of marriage could be influenced by this evolution.