See this online text:

  • “Every Marital Act Ought to be Open to New Life: Toward a Clearer Understanding”, by Germain Grisez, Joseph Boyle, John Finnis & William E. May. Reprinted from The Thomist, 52, 3 (July 1988): pp. 365-426 (copyright © Dominican Fathers, Province of St. Joseph, 1988). Available in pdf format through this page of The Way of the Lord Jesus.

On the anniversary of the issuance of the Encyclical “Humanae Vitae”. See also these related texts:

Other related texts are listed in the page “Marriage and the Family“. For other online texts and legally free ebooks, you may access the List of Free eBooks (Arranged by Title) and the List of Free eBooks (Grouped by Subject).

“[I]t is never lawful, even for the gravest reasons, to do evil that good may come of it (cf. Rom 3:8) — in other words, to intend directly something which of its very nature contradicts the moral order, and which must therefore be judged unworthy of man, even though the intention is to protect or promote the welfare of an individual, of a family or of society in general” (Pope Paul VI, Humanae Vitae, No. 14, as quoted by Pope St. John Paul II, Veritatis Splendor, No. 80)