This article analyzes the transformation of gender discourse within contemporary Catholicism after Vatican II Council. The author shows how numerous discussions among Catholic intellectuals and ordinary Catholics on gender equality, women's role in the church tradition, respect to sexual minorities and other out-groups historically discriminated within the traditionalist conservative approach are being actualized at the current stage of development of Catholic thought. Particular attention is paid to the comparative analysis of the gender concept interpretation on the part of secular and religious theorists. The transformation of gender discourse in Catholic thought is profound in nature and is related both to the development of scientific knowledge and the change in value orientations. That reflects the qualitative changes of religious and political identity. Carrying out the detailed analysis of current debate in the Catholic community linked with the Catholic complementarity theory, which shows the traditional understanding of gender, the author focuses on its critical reflection from the perspective of the later gender theories, in particular those proposed by Judith Butler. The author attempts to point out the interrelation between changes in the perception of gender issues among Catholics and the democratization process. Results of the Global Survey of Catholics' values are cited to confirm this thesis. Finally, the author carries out a comparative analysis of debates on the gender concept between so-called "conservative" and so-called "liberal" Catholic thinkers. The article notes the specific role of the French and American Catholic thought in the implementation of the gender mainstreaming. © 2018 Russian Presidential Academy of National Economy and Public Administration. All rights reserved.