Catechism of the Catholic Church §1607 — excerpt
According to faith the disorder we notice so painfully does not stem from the nature of man and woman, nor from the nature of their relations, but from sin.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.