Priestly celibacy in the Roman Catholic church has largely broken down in many parts of the world, Father Timothy Radcliffe, former master general of the Dominican Order, which has 200,000 members worldwide, said last night.
Fr Radcliffe, now a monk in Oxford but tipped by some as a future leader of the Roman church in England, said the church might have to consider ordaining married priests.
On the BBC Radio Four programme Analysis, broadcast last night, he said: "It is clearly the case that in many parts of the world celibacy has actually largely broken down - in many countries in Latin America, parts of Africa, to some extent in the United States...
"If it turns out to be the case that it is being largely ignored or bypassed, then... a very negative witness is being given; and so we have to ask is it possible now - either we have to provide celibate priests with considerably more support or we have to explore the possibility of them being married."
The Vatican and the Pope have rejected any question of altering the 1,200 year-old rule, but there is growing alarm in the church that the number of men coming forward to train for the priesthood in Europe and the US is declining, and that a high proportion of those in training are thought to be gay.
The Pope blames the decline in new priests and the steady exodus of others to marry on moral decadence and indiscipline in the western world.
The church in England has already relaxed the rule to some extent by letting some married Anglican priests who left the Church of England remain in holy orders.
Eamon Duffy, professor of the history of Christianity at Cambridge, told Analysis: "There is a real danger in the western Catholic church that the clergy will become a profession for homosexuals... many are first class, marvellous priests but I think everybody sees that it would be undesirable to have the clergy predominantly homosexual."