Many Anglicans believe the Bible condemns homosexuality
The bitter row splitting the worldwide Anglican church apart is to be tackled at the highest level.
The archbishops who lead the church's 38 separate provinces are meeting in London to try to resolve their differences over gay and lesbian clergy.
The divisions are now so deep that nobody expects the archbishops will manage to agree a way forward.
And even if they do, they have no way of compelling their churches to accept it, so a split may be inevitable.
The dispute has simmered for years, but has come to a head because of three developments within the past few months.
A diocese of the Canadian church endorsed same-sex blessings; in England a gay man was nominated as a bishop, and then asked to stand down; and a gay priest has been elected a bishop in the US.
Many members of the 70-million-strong worldwide church - known as the Anglican Communion - believe the Bible teaches that homosexuality is always wrong.
Some believe homosexual activity is wrong, but accept that individuals cannot change their make-up: many of them therefore accept gay and lesbian clergy who remain celibate, giving their sexuality no expression and living solitary lives.
A third group, a sizeable minority in the UK and North America, believes sexuality is a matter of nature not choice, and accepts homosexual clergy, who for years have worked alongside their straight colleagues without any fuss.
Rowan Williams does not have the same power as the Catholic Pope
Much of the opposition to accepting gays and lesbians into the clergy comes from the newer churches of Asia and Africa, where the number of Anglican worshippers continues to grow on a scale not seen in the UK for many years.
But other African church leaders argue for a more liberal approach.
The Archbishop of Cape Town and leader (primate) of southern Africa, the Most Reverend Njongonkulu Ndungane, says the row is distracting the church from tackling HIV/Aids and the Middle East.
Persuade and cajole
So a meeting of minds when the primates gather on 15 and 16 October at Lambeth Palace, the London home of the Archbishop of Canterbury, seems very unlikely.
One observer told BBC News Online: "The Anglican communion has no constitution, and the primates have never voted on anything in the time I've known them. If they made a decision this time it would be historic."
But even if the almost miraculous happens and the meeting does find a way through, the primates have no way to force their churches to accept what they say.
Each church is independent and self-governing, and most are themselves split down the middle on human sexuality.
So the new man on St Augustine's chair at Canterbury, Dr Rowan Williams, has an unenviable few days in prospect, trying to reconcile people whose real interest is in seeing their version of the truth prevail over everyone else.
Gene Robinson was elected Bishop of New Hampshire in August 2003
The archbishop is leader of the Anglican Communion, but that does not make him a sort of Anglican pope.
All he can do is try to persuade, cajole and finally remind his fellow primates of what still is supposed to unite them.
If he fails, the Anglican Communion seems bound to fall apart, with some members refusing to have anything more to do with those who take a different view.
At one of the most solemn moments of the Eucharist, the Anglican service - which for them is as sacred as the mass is to Catholics - priest and congregation together pray: "We are one body because we all share in one bread."
The liberal and thoughtful UK Anglican weekly, the Church Times, suggests that Dr Williams' best hope is to persuade the primates that prayer means more even than divisions over sexuality.