Catechism of the Catholic Church §1599 — excerpt
In the Latin Church the sacrament of Holy Orders for the presbyterate is normally conferred only on candidates who are ready to embrace celibacy freely and who publicly manifest their intention of staying celibate for the love of God's kingdom and the service of men.
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.