Evolution of thinking of the Catholic Church on the beginning of human life

The present teaching of the Catholic Church on the beginning of human life revolves around three non-negotiable principles: (i) protection of life in all its stages, from the first moment of conception until natural death; (ii) recognition and promotion of the natural structure of the family, as a union between a man and a woman, based on marriage; (iii) protection of the right of parents to educate their children. These principles are not truths of faith; rather they are inscribed in human nature itself and therefore are common to all humanity. Contemporary scholars state that ‘a human being is a person from the moment of conception’. As a consequence, there is tendency to abandon the ‘delayed animation’ theory of Thomas Aquinas, who argued that a human soul is created by God only after first a principle of organic life and then a sensitive soul have given it the required development. Today, Catholic teaching focuses on a total commitment for the defence of human life, ‘from conception to natural death’; as a consequence, ‘any human embryo – no matter how early – must be treated as a human person’. At the same time, official documents have purposely avoided taking a position on the question of ‘animation’, stating that it pertains to philosophy, not science.