Catechism of the Catholic Church §2215 — excerpt
Respect for parents (filial piety) derives from gratitude toward those who, by the gift of life, their love and their work, have brought their children into the world and enabled them to grow in stature, wisdom, and grace.
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.