Although contraception is not murder, the distinction between contraception and rhythm can be clarified by comparing it with the distinction between murdering a hopelessly ill person and withholding extraordinary means of care with the hope and expectation (the "intention" in the weaker senses) that he will die quickly and peacefully.
(Germain G. Grisez, "Reflections on the Contraception Controversy," The American Ecclesiastical Review 152 [May 1965]: 324-32, at 326-7)

