Celibacy Is a Rule, Not a Doctrine

The requirement that a Latin Catholic priest be unmarried is a discipline of church law, not a teaching about the nature of priesthood, and the church itself is explicit that it could be changed. The evidence is in the church's own practice: Eastern Catholic churches in full communion with Rome ordain married men, and so do the Orthodox churches, whose orders Rome recognises as valid without qualification. If celibacy were doctrinally necessary to priesthood, none of that would be possible.

The rule tightened slowly. Clerical marriage was common in the Western church for its first millennium, and the reforming councils of the eleventh and twelfth centuries, particularly the First and Second Lateran Councils, in 1123 and 1139, moved from discouraging it to declaring the marriages of clerics in major orders invalid. Property was a substantial part of the motive: married clergy had heirs, and heirs inherited church land.

There are married Latin-rite Catholic priests now. Married Anglican and Lutheran clergy who convert have been ordained under provisions dating from 1980 and extended by the personal ordinariates established in 2009. They are a small number and they are a standing demonstration that the rule is a rule.

A discipline can be dispensed. A doctrine cannot. The church treats celibacy as the first and the ordination of women as the second, and the difference between those two answers is the whole of the argument about what is negotiable.