Argentina's Jorge Mario Bergoglio, now known as Pope Francis I, takes the helm of a Roman Catholic Church that is facing numerous challenges. His predecessor, Pope Benedict XVI, left a legacy that was decidedly mixed. So what exactly is Francis up against?

1. The decline of Catholicism in the U.S. and Europe
The growth of Catholicism in Africa has been astounding, jumping from 55 million Catholics in 1978 to 146 million in 2007, according to USA Today. The story has been very different in the U.S. A new report from the Pew Forum on Religion & Public Life shows that the "percentage of U.S. Catholics who consider themselves 'strong' members of the Roman Catholic Church has never been lower than it was in 2012."

That translates to less people in the pews. In 1974, the percentage of Catholics who said they attended Mass at least once a week was 47 percent; in 2012, it was 24 percent.

The numbers are similarly bad in Western Europe, where weekly Mass attendance and the proportion of baptized Catholics are both at an all-time low, according to the Los Angeles Times.

2. Continuing sex scandals
The church's rolling sex abuse scandal has badly undermined the church's moral authority, and even tainted its most recent pontiff. In 1981, Benedict was Cardinal Ratzinger, the man in charge of the Vatican's Congregation for the Doctrine of the Faith, which is responsible for investigating claims of sex abuse. He would later be the subject of a lawsuit by the Survivors' Network of Those Abused by Priests (SNAP), which claimed he either "knew and/or some cases consciously disregarded information that showed subordinates were committing or about to commit such crimes."

The church hasn't come close to putting the scandal behind it. Just today, it was reported by the Daily Mail that the Roman Catholic Archdiocese of Los Angeles agreed to pay nearly $10 million to settle a sex abuse case involving former priest Michael Baker, who confessed to molesting children to Cardinal Roger Mahony in 1986, only to return to work after a short break. In 2009, Pew found that 27 percent of those who left the church said that the sexual abuse scandals had influenced their decision.

3. Women's demands for equality
The day before a conclave of men picked Francis as the new pope, female protesters from the Women's Ordination Conference set off a pink smoke flare on a hill above the Vatican. The message? "The current old boys' club has left our church reeling from scandal, abuse, sexism, and oppression," the group's leader, Erin Saiz Hanna, told Reuters. "The people of the church are desperate for a leader who will be open to dialogue and embrace the gifts of women's wisdom in every level of church governance."

The case of Rev. Roy Bourgeois, who was excommunicated in 2012 for participating in the ordination of a woman priest in Lexington, Ky., was a particular sore point for groups like the National Coalition of American Nuns. According to Reuters, in 2012 the Vatican appointed Archbishop J. Peter Sartain of Seattle to take over the Leadership Conference of Women Religious, which includes most nuns, in order to cleanse it of "radical feminist themes incompatible with the Catholic faith." Not exactly the message that will attract women in droves.