The top Catholic theologians in line for the Papacy come from diverse countries, backgrounds and many have courted controversyy over some more entrenched, traditional views of the church on issues like homosexuality and women.
Cardinal Marc Ouellet (ODDS 7/2)
Country of Birth: Canada
Current Position: Prefect of the Congregation for Bishops
Cardinal Marc Ouellet holds a mass at the Cathedral of St Peter
About: One of two current favourites, and the powerful leader of the arm of the Vatican that appoints bishop, the Cardinal told an interviewer in 2011 that to be Pope would "be a nightmare. I see the work the pope has to do. It is a huge responsibility. Nobody campaigns for it."
But he is fluent in six languages, learned and well-travelled throughout the Catholic world, which puts him in prime position.
Ouellet is a conservative, and testified before the Canadian senate, urging legislators to vote against legalising gay marriage, which he described as "pseudo-marriage, a fiction".
His most controversial remarks were made about abortion and rape, at an anti-aborion rally in 2010, where he said: "There's already a victim. Should we be making another one? Taking the life of another is always a moral crime."
But Ouellet showed his progressive side in 2007, when he published "An Open Letter To Quebec's Catholics" where he apologised for previous "discrimination against women and homosexuals."
He noted also that those "narrow attitudes of some Catholics, before 1960, have promoted Anti-Semitism, racism," and "indifference to the First Nations."
Archbishop Angelo Scola (ODDS 4/1)
Country Of Birth: Italy
Current Position: Archbishop of Milan
Cardinal Angelo Scola, Archbishop of Milan, celebrates mass
Not exactly a radical, reforming choice, he was described by the New York Times as a "conservative theologian" whose writings are "opaque", but he has a long-held interest in bioethics and Catholic-Muslim relations.
Catholic News calls him "Ratzinger but with a better popular touch. He's comfortable with the media, often better off-the-cuff than when he sits down and writes a speech. His texts can sometimes be dense, but his spontaneous commentary is accessible and informal with a good dose of humour."
Many have pointed to some of his more concerning views which appear in his book, The Nuptial Mystery, published in 2006.
In a review of the book in Commonweal magazine by Luke Timothy Johnson, the reviewer writes of Scola's "condemnation not only of abortion and of genetic engineering (cloning), and of birth control, but also of feminism, of homosexuality, and of cultural traits Scola associates with feminism and homosexuality, namely individualism, libertinism, relativism, narcissism, and even nihilism.
"The cardinal’s logic, in fact, seems to be that feminism is responsible for homosexuality, because the more women act like men, the more men are likely to want to have sex with other men."
Cardinal Peter Turkson (ODDS 9/2)
Country of Birth: Ghana
Current position: President of the Pontifical Council for Justice and Peace
Cardinal Peter Kodwo Appiah Turkson of Ghana gets his red hat from Pope John Paul II
Widely touted as the progressive choice, Turkson would be Africa's first Pope, from a region where Catholicism is growing fastest. He's young too, for a Pope.
Turkson caused outrage among former victims of sexual abuse by priests for linking progressive attitudes to homosexuality and child abuse.
In an interview with CNN, when asked about whether it was possible the Catholic sex abuse scandal could happen in Africa, the cardinal said it would not happen, "to the same extent or proportion as we have seen in Europe"
He continued: "African traditional systems kind of protect or have protected its population against this tendency.
He also sparked controversy in October 2012 when he screened a YouTube video that made alarmist predictions about the growth of Islam in Europe
Cardinal Francis Arinze (ODDS 10/1)
Country of Birth: Nigeria
Current Position: Prefect Emeritus of the Congregation for Divine Worship and the Discipline of the Sacraments
Nigerian Cardinal Francis Arinze attends a special mass celebrated by Pope Benedict XVI
He's too old to vote in the Papal election, and would be the oldest Pope in the history of the church. He's an outside bet, seeing as Pope Benedict XVI just announced he was retiring due to his advanced age - and is just three years older.
Neverless, he is a Vatican veteran, having spent 25 years there, and he was one of the contenders to replace John Paul II after his death.
His most controversial appearance was when he likened homosexuality with pornography, infanticide and adultery in a 2003 speech at Georgetown University.
"In many parts of the world, the family is under siege. It is opposed by an anti-life mentality as is seen in contraception, abortion, infanticide and euthanasia.
"It is scorned and banalized by pornography, desecrated by fornication and adultery, mocked by homosexuality, sabotaged by irregular unions and cut in two by divorce."
Cardinal Oscar Rodriguez Maradiaga (ODDS 12/1)
Country Of Origin: Honduras
Current Position: Archbishop of Tegucigalpa
Oscar Andres Rodriguez Maradiaga, first Catholic cardinal in Honduras, celebrates a Mass
More than half of the world's one billion Catholics live in Latin America, and Maradiaga would be the first Pope from the region.
He is described as charismatic with a denotation to social welfare issues, overseas aid and international development.
But Harvard academic Alan Dershowitz has accused Maradiaga of holding anti-semitic views, claiming he had said: “The Jews got even with the Catholic Church for its anti-Israel positions by arranging for the media — which they, of course, control, he said — to give disproportionate attention to the Vatican sex scandal.”
His comments refer to an interview given by the cardinal in 2002 in Italian Catholic publication 30Giorni.
The cardinal apologised profusely for his comment, according to Israeli newspaper Haaretz.