The decision of Londonderry cleric Fr Sean McKenna to leave the priesthood because he is in a relationship with a woman has raised again the issue of celibacy within the Catholic Church.

It is obvious from the reception given to Fr McKenna by his congregation when he broke the news to them on Sunday that he was much admired as a priest and that that admiration follows him into his life as a lay person. The sadness that many people feel is that he had to choose between his vocation and his new relationship.

The Catholic Church has for centuries held the view that priests must be celibate. That, like its strict views on issues such as abortion and divorce and the ordination of women, is one of the attractions of the Church to those seeking certainties in their lives. However, others see celibacy as an outmoded restriction on the lives of priests.

They would argue for its removal on a number of grounds. Firstly, that married priests with a family would be more able to recognise the trials and tribulations of their flock if they endured those same trials and tribulations themselves. Secondly, enforced celibacy is seen as one of the obstacles to more young men coming forward for ordination. There are genuine fears that in the near future Ireland, which once sent missionaries to every corner of the world, will depend on clergy from developing countries to help man all its parishes.

The admission of married clergy from the Anglican Church to full priesthood in the Catholic Church is seen as eroding the principle of enforced celibacy.

Many people will ask validly how there can be one rule for one set of clergy and another rule for traditional Catholic priests.

There is little likelihood of the celibacy rule being swept away in the near future, but more and more Catholics - within the clergy as well as the laity - are openly questioning if it serves any purpose any longer.