The dignity of a person must be recognised in every human being from conception to natural death. This fundamental principle expresses a great yes to human life and must be at the centre of ethical reflection on biomedical research, which has an ever greater importance in today’s world . The Church’s Magisterium has frequently intervened to clarify and resolve moral questions in this area. The Instruction Domun vitae was particularly significant. And now, twenty years after its publication, it is appropriate to bring it up to date with this publication from the Congregation for the Doctrine of the Faith.