Miss Marple gives some practical considerations. She is quite correct in saying that this is a matter of "discipline" and not dogma. In other words, it is conceivable that it could be changed in particular circumstances.
However, from a theological perspective, Jaysun, there is only ONE HIGH PRIEST, and that is Jesus the Christ. The men we call priests confect the Eucharist "in persona Christi"--in the person of Christ--and are therefore called "alter Christi" or other Christs as they represent Him who is the High Priest. Since Christ was unmarried and fully involved in only one work, the salvation of mankind, priests are called to do likewise.
This then explains those parts of Scripture that indicate that anyone who leaves mother, father, wife, family to follow Christ will have 100 fold greater families. This is one of the many reasons for the discipline of celibacy and why it is unlikely to ever be overturned in the Roman Church. Priests follow Christ in every way including His style of Life. Christ, in the Catholic view, has the Church as His Mystical Body. The Church is also His bride. So does the priest and it explains our viewpoint: he is married to the Church of Christ.
http://www.usccb.org/catechism/text/pt1sect2chpt3art9p2.htm
See #796
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