Three years ago, 35 Republicans voted in favor of a bill that would expand anti-discrimination laws to gays and lesbians, but with Democrats proposing to add transgender people to the measure, far fewer members of the minority party are likely to support it if it comes to a vote this year.

Two dozen Republicans still in the House voted to support the Employment Non-Discrimination Act in 2007, which barred employers from discriminating against employees based on sexual orientation. Language that included transgender individuals was stripped out of the final bill by Financial Services Chairman Barney Frank (D-Mass.), the lead sponsor who said at the time that the language would have killed the bill because of opposition from conservative Democrats and Republicans.

During the debate over the 2007 ENDA bill, Rep. Tammy Baldwin (D-Wis.) offered an amendment that included the transgender language but pulled the measure before it received a vote.

The bill passed the House 235-184 but stalled in the Senate. Even if it had passed both chambers, President George W. Bush indicated he would have vetoed it.

Even with a friendlier administration in the White House, Democrats still face opposition to the measure within their Caucus and could have trouble getting the votes necessary to pass it if the transgender language remains intact. Democratic leaders have not yet scheduled a markup of the bill because they are still trying to gauge Democratic support. At the moment, there are 202 co-sponsors listed on the bill.

The measure already faced diminished Republican support; 14 of the 35 Republican who voted for the bill in 2007 did not return to the House in 2008.

Those Republicans who have remained in the House are suggesting that their support for the bill may turn to opposition if the final bill extends protection to transgender individuals. Only one freshman Republican, Rep. Leonard Lance (N.J.), is listed as a co-sponsor of the 2009 version of the bill.

“That’s an issue,” said Rep. Judy Biggert (R-Ill.), who is listed as a co-sponsor of the bill that includes transgender people. “I just haven’t decided.”

Biggert said she had met with transgender people and had initially intended to vote for the bill, but became concerned when she began to think how the expansion of the law could affect schools.

“It’s just in the schools … I worry about teachers, that’s probably it,” she said. “I have to make up my mind, I guess.” Conservatives have raised concerns that the new language would give parents no recourse if their kids were assigned to a class with a transgender teacher.

Rep. Patrick Tiberi (R-Ohio) said the transgender language gave him pause as well.

“I think it’s going beyond what the original intent was,” he said.

Rep. Greg Walden (R-Ore.), a former small-business owner, said the transgender language would put employers in a difficult situation.

“I’m evaluating [the bill] in that context,” he said. “I don’t believe in discrimination in the workplace … but this may just be a step too far.”

A spokeswoman for Rep. Mario Diaz-Balart (R-Fla.) said her boss is still reviewing the measure.

A spokesman for Rep. Frank LoBiondo (R-N.J.) declined to comment, saying he could not comment on the contents of a bill that was still being drafted in committee.

Other Republicans said Frank would lose their votes if the transgender language were included.

“They probably lose me if they do that,” Rep. John Campbell (R-Calif.) said. “That just moves it too far.”

Campbell said, “This is a very small number of people that do a very extreme thing, have a very extreme surgery. … I think employers probably have an argument for some discrimination on that in some cases because it is so far out of the mainstream and can be readily apparent.”

Rep. Jeff Flake (R-Ariz.) said he made it clear in 2007 that he opposed the inclusion of transgender people in the bill and that he would not vote for it again if it were included.

“It’s too nebulous,” Flake said. “I think it’s just not clear-cut enough.”

Rep. Paul Ryan (R-Wis.) also said he would likely vote against the legislation with transgender protections, and he said he’s told Frank as much.

“It makes it something you can’t vote for,” Ryan said. “I think ENDA’s the right thing to do,” but transgender language “changes the equation.”

Ryan declined to detail his objections, saying he wanted to read the final package.

Not all Republicans plan to jump ship.

“I certainly would lean toward supporting it,” said Rep. Mike Castle (R-Del.), who — like Biggert — is a co-sponsor of the bill that includes protections for transgender people. “Nothing gives me pause necessarily, I would just want to review it and make sure that it meets all my standards.”

Republican Reps. Mary Bono Mack (Calif.), Ileana Ros-Lehtinen (Fla.), Mark Kirk (Ill.) and Todd Platts (Pa.) said they would support the bill with the transgender language.

“Individuals should be judged on their merits [and] on their work ethic, not on their sexual orientation,” Platts said.

Frank said he has always understood that there was a problem with the inclusion of the transgender language but said once the provisions are explained it becomes less of an issue.

“We never counted on 35 Republican votes,” he said. “Yes, I expect to lose votes, but we have votes to lose.”

Steven T. Dennis contributed to this report.