Intentional Structure of Act

Anscombe On Intentions in Contraception vs. NFP

“Contraceptive intercourse and intercourse using infertile times may be alike in respect of further intention, and these further intentions may be good, justified, excellent. .. But contraceptive intercourse is faulted, not on account of this further intention, but because of the kind of intentional action you are doing.  The action is not left by you as the kind of act by which life is transmitted, but is purposely rendered infertile, and so changed to another sort of act of altogether.”

- Elizabeth Anscombe, "Contraception and Chastity"