Abstract
For the Catholic religious authorities, the biological proces ses through which human life is reproduced, for the simple reason that they are "natural", contain a normative value for action and thus become a moral standard. This conviction governs the action they take in connection with both abortion and contraception. This postulate makes sense within the neo-scholastic interpreta tion of Thomism. It is questioned by critical Thomism, and more radically by a line of thought inspired by Kant, which connects the ethical problem with a theory of action. It is alien to Protestant theology whose biblical, but also Kantian, inspiration makes ethics autonomous.