The Gospel of Life is not for believers alone: it is for everyone. The issue of life and its defense and promotion is not a concern of the Christian alone. Although faith provides special light and strength, this question arises in every human conscience which seeks the truth and which cares about the future of humanity. Life certainly has a sacred and religious value, but in no way is that value a concern only of believers. The value at stake is one which every human being can grasp by the light of reason; thus it necessarily concerns everyone.
--Pope St. John Paul II