WASHINGTON — Mitt Romney will address an anti-abortion group tonight, one day after he assailed the Reverend Al Sharpton for his comment that “those who really believe in God” will defeat the former Massachusetts governor in his bid to become the first Mormon president.

“It shows that bigotry still exists in some corners,” Mr. Romney told reporters in Iowa, according to the Associated Press. “I thought it was a most unfortunate comment to make.”

The dust-up stemmed from a remark that Rev. Sharpton made on Monday in the middle of a debate about God with the author Christopher Hitchens, who is releasing a book titled, “God is Not Great.”

“As for the one Mormon running for office, those who really believe in God will defeat him anyways, so don’t worry about that; that’s a temporary situation,” Rev. Sharpton said at the event, which was held at the New York Public Library.

Rev. Sharpton, a former Democratic presidential candidate, said afterward he was not referring to Mr. Romney’s Mormon faith and attacked his campaign for what he called a “blatant effort to fabricate a controversy to help their flagging campaign.”

“What I said was that we would defeat him, meaning as a Republican,” Rev. Sharpton told the Associated Press. “A Mormon, by definition, believes in God. They don’t believe in God the way I do, but by definition, they believe in God.”

Yet late yesterday, his office released another statement in which Rev. Sharpton appeared to take the Mormon issue head on regarding the religion’s previous support for segregation policies. “Maybe one should ask Mr. Romney whether these were the articles of faith of his church to preach segregation and whether he was a member of the church at that time,” he said.

It is an open question whether Mr. Romney’s Mormon faith will hinder his effort to win the Republican nomination. He is fond of saying that reporters ask him about it much more frequently than potential voters do. He also often says that Americans want a “person of faith” in the White House but that they don’t particularly care what that faith is.

Mr. Romney has taken a similar approach on the campaign trail, discussing his belief in God but not focusing on the specifics of Mormon doctrine. He will likely do so again tonight in his speech to the Massachusetts Citizens for Life, where he will also have an opportunity to draw contrasts between himself and Mayor Giuliani, who supports abortion rights.

Mr. Giuliani’s position has come under increased scrutiny in the last week, first when he said it would be “okay” if the Supreme Court overturned Roe v. Wade and more recently after the disclosure that he made at least six personal donations to Planned Parenthood, a leading abortion-rights group.

Mr. Romney, who is unlikely to criticize the former mayor directly tonight, also has a complicated history on the issue. He favored abortion rights when he ran for the Senate in 1994 and for governor in 2002, but he has said he changed his mind while considering the ethical implications of stem-cell research in 2004. His foundation gave $15,000 to the Massachusetts Citizens for Life in 2005, and the group is tonight giving him its Political Leadership Award.

ABC News reported last night that Mr. Romney’s wife, Ann, had also made a small donation to Planned Parenthood in 1994.