Catholics call their Priest “Father,” yet Christ said “Call no man your father upon earth.” Matt. XXIII, 9.
Your rigid interpretation would forbid your calling an earthly parent father. Yet God Himself, in the commandments, terms one of your parents father, and tells you to honor him as such. Your text means simply, “Call no one your father as if you had no other father with rights over you.” That is, you must realize that all paternity is of God, and that you owe your being, and all that you have, including your earthly father, to Him. Nor can any claims of an earthly father avail against our duties to God, our heavenly Father. Meantime, Catholics do not call a Priest “Father” in the same sense as that in which they call God their Father. A Priest, by God’s Providence and by the authority of Christ, is a father in the spiritual sense, just as a natural parent is a father in an earthly sense. By administering Baptism he gives spiritual life to a soul; he nourishes that life by conferring the Sacraments; he warns, teaches, helps with his advice, corrects, and does all in the spiritual life that an earthly father does in the temporal order. So much so that St. Paul attributes a true paternity to himself, saying, “I admonish you as my dearest children … for in Christ Jesus, by the Gospel, I have begotten you.” I. Cor, IV., 14.
The Pope, Question 380 from Radio Replies Volume I Copyright © 1938 (by Rev. Dr. Leslie Rumble, M.S.C. and Rev. Charles Mortimer Carty).