Senator Arlen Specter's record on gay rights is threatening to undermine his re-election bid as Republicans continue attempts to turn the campaign into a referendum on gay marriage and the military's ban on open gay service – dicey issues for the Pennsylvania Republican-turned Democrat.

Specter has disavowed many of his previous positions on gay rights, prompting accusations from fellow Democratic rival Pennsylvania Republican Joe Sestak that the 80-year-old senator is not “honest” or “loyal.”

The latest evidence that gay rights are moving back to the front burner of the contest came Thursday when Republican opponent Peg Luksik likened gay marriage to incest.

Luksik, who is among the six candidates hoping to unseat Specter, made her comments during a candidates forum held at Cheyney University and sponsored by the campus branch of the NAACP. Both Specter and primary rival Sestak skipped the event. The men were represented by spokespersons.

When asked about the military policy that bans gay troops from serving openly – commonly known as “Don't Ask, Don't Tell” – Luksik, a Johnstown Republican, likened gay marriage to incest.

“If a marriage license is a fundamental human right then anybody should be allowed to have a marriage license with anybody,” the Daily Times quoted her saying.

“So I can have one with my sister, my brother, you can have one with your parent, because if it's a fundamental right for anybody to marry anybody, then it's a fundamental right for anybody to marry anybody,” she added.

Luksik's remarks might be bait to Specter on issues that have already proved thorny for the senator. In a blog post published last year in the Huffington Post, Specter said it was time to repeal the Defense of Marriage Act (DOMA), the law that defines marriage as a heterosexual union for federal agencies, and “Don't Ask, Don't Tell,” reversing his long-held views on the issues.

Specter's rival for the Democratic nomination, Representative Joe Sestak, was more than happy to remind voters of Specter's record.

“As the longtime Republican senator carries on his attempt to run away from his 30-year Republican record, this time on his vote to support the Defense of Marriage Act, he should be honest about his votes to oppose equal rights for LGBT Americans. He actually voted with Republican Senator Rick Santorum to deny equal benefits to legally married LGBT Americans in the first place,” Sestak said. “Senator Specter's willingness to reposition himself just to help himself politically should give pause to Pennsylvanians who are looking for a loyal senator who will put principle over politics for the next generation.”

Complicating matters is a nearly evenly divided electorate on gay rights. For example, Pennsylvanian lawmakers appear to have reached a stalemate on gay unions. Neither a gay marriage bill nor one that seeks to ban gay marriage have gained much traction at the Statehouse. One lawmaker, Representative Mark Cohen, says civil unions are the best compromise. The Democrat introduced a bill that recognizes gay couples with civil unions last month.

Whether Republicans are ratcheting up their rhetoric on gay rights in an effort to rattle Specter remains to be seen, but Luksik, who will face her primary opponents on May 18, appears certain to continue to press her opposition to gay rights: “I support the traditional definition of marriage as the union between one man and one woman,” she says on her campaign website.