ABSTRACT
Popular expositions of Roman Catholic teaching on sexual morality often conflate contraception and abortion. Elizabeth Anscombe did not do this; instead she explicated the concepts of act and intention and constructed a powerful though somewhat intricate defence of Catholic rulings on birth control understood as contraception. An act of contraceptive sex can be intrinsically non-generative either qua physical act or qua intentional act. Anscombe further argues that safe period sex, deliberately chosen with the intention of avoiding conception, is not condemnable, provided there is good reason to avoid conception in the particular case. In the former case the intention to avoid conception is a cause or part-cause of the act’s being infertile. The fact is that nobody knows whether the occurrence of the intention as cause is in every case necessary, or sufficient, or both, or neither, to determine the intrinsic character of an intentional act.
