Pope Francis has been asked to consider allowing married men to be ordained in remote regions of South America, challenging the Catholic church's long-held views on celibacy for its priests.
An assembly of Roman Catholic bishops from the Amazon region of South America have called for the changes because of a severe shortage of priests.
Pope Francis is considering the proposal after it passed by 128 votes to 41.
"I would like to underline something: we have not yet realised what women mean to the Church," Francis told the synod.
"We talk about them only in regards to the functional part, which is important, but the role of women in the Church goes far beyond functionality."
At least 85% of Amazon villages cannot attend Mass every week and some have been unable to do so for years.
The issue of a married priesthood for the Amazon region was by far the most contentious item in a 120-paragraph final document.
The proposal calls for married men who are already deacons in the Church, have a stable family relationship, and are proven leaders in their communities to be ordained as priests.
Conservatives oppose the change, fearing it would be a slippery slope leading to a married priesthood throughout the 1.3 billion-member church.
They fear that if one part of the church was allowed to ordain married men as an exception, there would be nothing to stop other areas with a shortage of priests following suit.