The Church of England was debating whether to allow female bishops for the first time in its history before a vote Monday, which could end half a century of bitter divisions over the role of women.
A yes vote by its governing body, the General Synod, could see the first women appointed to the Anglican Church's top jobs by the end of this year.
Although the idea of female bishops was rejected in 2012, senior church figures are optimistic it will pass this time after a careful reconciliation process involving figures who worked to bring peace to Northern Ireland.
The Church of England is the mother church of the global Anglican Communion, followed by some 80 million people in over 165 countries.
Archbishop of Canterbury Justin Welby will speak in favour of the motion at the meeting in York, northern England, later and says he is "hopeful" of a yes vote.
His de facto number two, Archbishop of York John Sentamu, hinted at the frustration among top clergy over how long it has taken to resolve the issue as he opened the debate.
"This is the third time in two years we have embarked on a final approval debate on women bishops -- you ought by now to be getting the hang of it," he joked.
A string of supporters of the move made their views heard on the floor of the General Synod as the debate started.
The Bishop of Rochester in south-east England, James Langstaff, said the Church had a "responsibility to show that we are listening".
"I think and believe this is the moment for us to vote yes," he added.
Emma Ineson, principal of a theological college in Bristol, south-west England, said her female students had been "dismayed, confused, discouraged" by the 2012 no vote.
"Please can we not do that to them again?" she added.
If the move again fails to pass with the necessary two-thirds majority in three houses of the Church of England, officials could be set to take drastic action.
The Guardian reported last week that options to force through change if necessary are being considered, including passing legislation through bishops sitting in the House of Lords.
Any move to let women take the top positions in the Church of England is fiercely opposed by traditionalist Anglo-Catholics, who believe that only men should be priests and bishops.
But some of those who had been opposed to the principal of women bishops in the past are now backing this set of proposals, including some who voted no in 2012.
Measures, including an assurance that those opposed to women bishops will be able to ask to be ministered to by a male bishop, have been included to try to assuage their concern.
The result of the vote is thought to be on a knife-edge -- in 2012, it was defeated by just six votes from lay representatives of the Church.
The first women vicars were ordained in the Church of England in 1994, but the issue of women's role in the Church has been debated for at least 50 years.
"The time has come now to sort it out and get on with it," said Canon Jane Hedges, Dean of Norwich in eastern England, who is tipped as a potential future bishop.
"There are so many enormous issues facing our world and so much real need -- in a sense this distracts us and absorbs a lot of energy," she told AFP.
There are already Anglican women bishops in other countries, including the United States and Australia.
While a yes vote would not force Anglican churches in other countries to allow women bishops, senior clergy say it would send a powerful message that should prompt others to follow.
If the vote does pass, it would need to be debated by parliament, approved by Queen Elizabeth II and then come back to the General Synod in November as a formality before taking effect.