But at least some supporters of Moore in Alabama are standing by him, saying they don't believe the allegations.
“I think most conservative Christians are going to vote for him because they believe in him,” Nancy Fluker of Wilsonville, Alabama, about 32 miles southeast of Birmingham, told ABC affiliate WBMA-TV in Birmingham. “They believe in his reputation. They believe in his record."
Some political observers in Alabama said they think fallout from the allegations against Moore may depress turnout at the polls and that many Republicans may choose to write in another name rather than vote for the former judge.
"I imagine there are going to be certain people who will not want to vote for the Democrat, but who will not want to vote for [Moore] and I imagine that there will be a write-in," said former Alabama Supreme Court Justice Gorman Houston who ran as a Republican but now considers himself an independent. "A lot of people will write in" candidates, he said.
But in Shelby County, Alabama, on the outskirts of Birmingham, many who spoke to WBMA-TV said they are sticking by Moore.
Nancy Fluker and her husband, Gordon, said they believe Moore's denial of having had a sexual encounter with a 14-year-old when he was 32.
“I believe him that he didn't do it,” Gordon Fluker said. “I think it's something someone waited until an opportune moment to put on the news across the world, to downgrade him.”
Similarly, Susan Conn, who owns Main Street Florist in downtown Columbiana, Alabama, told WBMA-TV, she is suspicious of the timing of the allegations.
“I just don't see how he could be guilty now and not be guilty in all these other elections” in which he ran, Conn said.
Conn said she voted for Moore's Republican rival in the primary runoff, Luther Strange, but will now vote for Moore in the general election.
“Him being a Christian, I would hate to know he's guilty of anything like that,” said Conn. “He really does seem like he does what he thinks he's supposed to do. I just don't believe he's guilty.”
Houston, the former Alabama Supreme Court justice, said Moore has a group of loyal supporters who are unlikely to abandon him.
Houston served on the state's high court during a battle over Moore's monument to the Ten Commandments that he placed in the state judicial building in Montgomery.
Moore was elected chief justice of the state Supreme Court in 1999 but was removed in 2003 by the Alabama Court of the Judiciary for “willfully and publicly” defying a federal court's orders to remove the monument.
Houston said that when he disagreed with Moore about the appropriateness of the monument, he received hate mail from supporters of his fellow judge.
"Just the hate that they had for those of that did not go along with Roy Moore. It was really something," Houston said.
ABC News' MaryAlice Parks contributed to this story.