In view of the Church’s divine mission it is not surprising that some of her moral teachings are not self-evident to secular man. However she has usually offered supporting reasons for her position and no disloyalty is involved in questioning whether these are really valid. In the case of direct sterilisation Pius XI, in Casti Connubii, presents the classical argument for prohibition (frequently to be repeated by Pius XII) and specifically states that his conclusion is one that ‘the light of human reason makes most clear’. In this article I want to suggest that there are many good men, even within the Christian tradition, to whose reason the prohibition of sterilisation is far from clear and, furthermore, that even the classical arguments may need to be reviewed in the light of new developments. I am not going to discuss the various medical, psychological and economic factors involved, since their bearing on the central moral problem is indirect.

The argument that secular man might put forward to support direct sterilisation could take the following form: There are many instances in which a married couple would have reasons of conscience to refrain from further conceptions; such possible reasons are in fact suggested by Pius XI in his encyclical. They could be of such gravity that the only way in which the risk could be responsibly avoided would be by permanent abstention from sexual intercourse or by sterilisation. The first solution, it would be readily admitted, carries certain dangers such as the straining or even breakdown of the marital home with consequent damage both to the existing family and to society at large.