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Peter Morrison, Associated Press
Carmelite sisters cast their vote at a polling station in Malahide, County Dublin, Ireland, Friday, May 22, 2015. Ireland began voting Friday in a referendum on Gay marriage which will require an amendment to the Irish constitution.

DUBLIN — Ireland's voters were deciding Friday whether to legalize gay marriage in this once-staunchly Catholic land in what the government's equality minister called "a referendum like no other."

Opinion polls throughout the two-month campaign suggest the government-backed amendment favoring gay marriage should be approved by a majority of voters when results are announced Saturday. But gay rights activists expressed caution, based on previous votes when anti-government sentiment and low turnout produced surprise referendum rejections.

Electoral officers reported stronger-than-usual voter turnout at polling stations in schools, church halls and pubs across this nation of 3.2 million registered voters. Some lines built up outside stations before the 7 a.m. opening. On social media, voters traveling in from as far away as Australia posted their progress and voting intentions. Most were saying "yes."

Voters leaving one polling station in northeast Dublin, a Catholic parish hall, demonstrated a clear generation gap when asked how they had voted. Those under 40 were solidly "yes," older voters much more likely to have voted "no."

"You can give the gays their rights without redefining the whole institution of marriage. What they're asking for is too much," said Bridget Ryan, 61, as she voted with her border collie in tow.

On Twitter, travelers documented their disparate journeys home to Ireland via London, New York, Bangkok and Nairobi, often under the hashtags #HomeToVote or, for those in neighboring Britain, #GetTheBoatToVote. One posted a picture on a London-to-Wales train with travelers donning the rainbow colors and balloons of the gay rights movement.

The government's minister for equality, Aodhan O Riordain, cast his "yes" ballot in northeast Dublin, declaring it the most important vote of his life. He took heart from early signs of a strong turnout, since involvement by young, first-time voters is considered key for the gay rights measure to pass.

"There's been queues outside registry offices to get people to vote. There's been queues of people trying to get their identification stamped in order to register to vote. There's been packed-out meetings up and down the country. There's been people wearing badges for months saying they're going to vote 'yes,'" the 38-year-old said.

"This is a referendum like no other," O Riordain told The Associated Press. "There's a buzz and an anticipation of this like I've never seen before."

Leaders of the country's predominant faith, Roman Catholicism, have fueled opposition to the measure, arguing that legalization of gay marriage would undermine the institution and trigger unintended legal consequences in Irish courts, where adoption and surrogacy rights loom as distinct legal battlegrounds.

A "yes" result would provide fresh evidence of waning church influence in a country that, in the 1980s, voted forcefully in referendums to outlaw abortion and reject divorce.

By the shores of Dublin Bay, 20-something campaigners from the Yes Equality lobbying group waved rainbow flags and held up placards urging morning commuters to "Vote for us." Cars honked back in approval.

The Students Union of Ireland, determined to spur students back to their often faraway home districts to vote, produced an app offering custom-tailored advice on the best transport links to take. Cab booking companies Hailo and Uber offered free lifts to polling stations.

Irish singer Hozier posted a selfie in which he held up a Yes Equality "I'm ready to vote" sign. "Flying in to vote. ... It's the most important thing you'll do. Don't forget!" he wrote.