Catechism of the Catholic Church §2343 — excerpt
Chastity has laws of growth which progress through stages marked by imperfection and too often by sin. "Man . . "129
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.