Bishops from the Amazon region had sought the changes to address a shortage of clergy. But some Roman Catholic conservatives warned that enacting them would lead to the end of clerical celibacy rules.
The surprise move is seen as a rebuke to Pope Francis, who is weighing whether to allow older, married men to be ordained in some South American countries, where a shortage of priests is acute.
A #NunsToo movement has emerged from #MeToo, as Roman Catholic nuns start speaking out about sexual abuse by priests. Cases of rape and forced abortion have begun coming to light.
The raid came days after three bishops in Chile resigned over the church's decades-long sex abuse and coverup.
Pope Francis questioned survivors' accounts and defended a Chilean bishop accused of a coverup. But the Vatican announced Tuesday that a top envoy will now look into survivors' claims.
"These numbers are shocking, they are tragic and they are indefensible," says a church representative. More than 4,400 people reported allegations of abuse at more than 1,000 different institutions.
The Catholic Church in the U.S. has been aging, along with its dwindling priestly ranks. But in the increasingly secular world, there's been a recent uptick in younger men studying to become priests.
Monsignor Krzysztof Charamsa appeared at a news conference with his partner. In an interview he called the Church's stance on homosexuality "backwards."
Justin Welby, the spiritual leader of the Church of England, hopes the gathering can resolve a growing rift over female priests and same-sex relationships.