With every Republican in opposition, the House of Representatives voted 77 to 62 Thursday night for legislation barring discrimination against perhaps one of the last unprotected minorities, the transgender population.

The bill barring discrimination on the basis of gender identity applies to employment, housing and public accommodations, including the use of restrooms – a topic that dominated the five-hour debate.

The bill, which now goes to the Senate, was considered an unfinished piece of business by the “LGBT community,” the coalition of lesbian, gay, bisexual and transgender activists who helped pass the state’s first gay rights bill 20 years ago.

“It’s a continuation of protecting a minority against discrimination,” said Betty Gallo, a lobbyist on the first gay rights bill and the more recent gender identification measure.

Much of the debate focused on public bathrooms: Which bathroom should be used by someone whose sexual identity is in doubt? By someone who might still have male genitalia, but dresses, lives and appears to be a woman?

Opponents questioned the need for the bill and suggested it might give legal protections to someone who indulges in a whim to dress as the opposite sex.

“Today, I feel like a woman,” said House Minority Leader Lawrence F. Cafero Jr., R-Norwalk, imagining himself as a man wanting to use a ladies room. “If you don’t let me, I’m going to sue you.”

“This is not right,” said Rep Penny Bacchiochi, R-Somers.

To the proponents, the passage was about broader protections against being fired or evicted over their gender identity. The bill has been offered for years without success.

“One of the things we’ve learned over time is this is not a whim,” said House Majority Leader J. Brendan Sharkey, D-Hamden. “This is something very wrenching for the person who deals with these issues on a day to day basis.”

Gov. Dannel P. Malloy, whose legal counsel had testified in support of the measure at a public hearing, has promised to sign the bill if it clears the next hurdle: debate in the Senate.

Malloy’s support became an issue for Republicans.

Cafero said he did not seek a caucus position on the bill, leaving the 48 Republicans present to rely on their own values and reasons for opposition. Fourteen Democrats joined them. (A roll call can be viewed here.)

“We are now in a place where every vote has become a partisan pitched battle,” Cafero said.

Cafero said the GOP resented what he called the administration’s heavy-handed lobbying to round up votes for the bill and against Republican amendments.

“The governor was behind this bill, using every asset and resource to help lobby the bill,” Cafero said. “He had his staff twisting arms.”

Michael P. Lawlor and Andrew McDonald, who were co-chairs of the legislature’s Judiciary Committee until resigning to join the Malloy Administration, were present during parts of the debate.

McDonald said he testified in support of the bill before the Judiciary Committee at Malloy’s direction — something he mentioned during the public hearing — and that Malloy had submitted testimony in support of previous versions while he was the mayor of Stamford.

“The governor has been a longstanding supporter of this legislation, and he very much looks forward to signing it,” McDonald said during his testimony in March.

Gallo handed out copies of the testimony as she lobbied House members.

“His support of this legislation has been unwavering and consistent,” McDonald, the governor’s legal counsel, said after the vote. “His support has not been secret.”

House Speaker Christopher G. Donovan, D-Meriden, called the vote a proud moment for 77 Democrats in the House and a statement against bigotry and discrimination.

“It might not be politically expedient, but it was the right thing to do,” Donovan said.

Donovan dismissed the idea that the GOP vote might have been a reaction against the governor’s support.

“In the end, your vote is for what you believe is right,” he said.

Debate became heated at times, as some Democrats questioned what lay behind the opposition of some Republicans. Some of those questions came on the House floor. One came on a Twitter comment posted during the debate.

Rep. Matthew Lesser, D-Middletown, said in a tweet: “Tonight’s debate on adding gender identity & expression to state’s non-discrimination laws being hijacked by ugly fear-mongering.”

It was not unnoticed by Republicans, who responded in real-time on the House floor. He was reprimanded by Rep. Pamela Sawyer, R-Bolton, for questioning a member’s motives, a violation of House rules and etiquette.

Lesser was unapologetic.

“I tweeted what I tweeted,” Lesser said. “And I believe it sincerely.”