Stem cell research regulations are highly variable across nations, notwithstanding shared and common ethical concerns. Dominant in political debates has been the so‐called embryo question. However, the permissibility of human embryonic stem cell (hESC) research varies among national regulatory frameworks. Scholars have explained differences by resorting to notions of political culture, traditions of ethical reasoning, discursive strategies and political manoeuvring of involved actors. Explanations based on the role of religion or other cultural structural variables are also employed. This paper analyses the emerging of the Italian regulatory framework on stem cell research using an analytical framework that considers the interplay between cultural structural features, political culture, traditions of ethical reasoning, institutional settings and the discursive and political agency of the actors involved. It aims also to explain the role of Roman Catholic Church in shaping the Italian stem cell research regulation not by treating religion as an autonomous causal factor, but through the analysis of the agency of Catholic and allied actors in the Italian political culture and institutional setting.