He said that "many priests have found it very difficult to cope with celibacy," and while he had never considered marriage himself, he told BBC Scotland that "the celibacy of the clergy, whether priests should marry – Jesus didn't say that."
"I would like others to have the choice. In my time there was no choice, you didn't really consider it too much. It was part of being a priest when I was a young boy, priests didn't get married and that was it. When you were a student for the priesthood, well it was part of the package, as it were, that you were celibate, that you didn't get married and you didn't really consider it all that much, you just took your vows of celibacy the way someone else would naturally take their vows of marriage."
O'Brien, 74, stood down from some higher duties in the Roman Catholic church in Scotland last year due to his advanced age, but he will form part of the conclave of cardinals that chooses the next pope, following the resignation of Pope Benedict XVI on Feb 28.
The cardinal said the next pope should be free to consider changing church policy that were not "basic dogmatic beliefs." He said that "we know at the present time in some branches of the church – in some branches of the Catholic church – priests can get married, so that is obviously not of divine origin and it could get discussed again," referring to traditionalist Anglican clergy who were married before converting to catholicism. The pope granted dispensation for them to be ordained into the Roman Catholic Church as priests despite being married.
Though he seems to support marriage for clergy, O'Brien has long been a vocal opponent same-sex marriage in Scotland and was named "bigot of the year" by the gay rights charity Stonewall last November. It said he was given the title because he went "well beyond what any normal person would call a decent level of public discourse" in the debate.