Can. 277 §1. Clerics are obliged to observe perfect and perpetual continence for the sake of the kingdom of heaven and therefore are bound to celibacy which is a special gift of God by which sacred ministers can adhere more easily to Christ with an undivided heart and are able to dedicate themselves more freely to the service of God and humanity.
http://www.vatican.va/archive/ENG1104/__PY.HTM
Priests are called to serve God and His Church with an “undivided heart”, a virtual impossibility when one has a wife and kids to consider. Exceptions have obviously been made, but priestly celibacy remains the ideal, for both spiritual and practical reasons.
I’m quite in accord with the tradition and discipline of priestly celibacy. No argument here.