Massachusetts Representative Barney Frank (Democrat) has said he is “very disappointed” by President-elect Barack Obama's choice of megapastor Rick Warren to give the invocation at this inauguration. Frank spoke Sunday on CNN's Late Edition.

Gay rights groups began protesting the pick on Wednesday – immediately after it was announced – saying Warren was homophobic.

“I am very disappointed by President-elect Barack Obama's decision to honor Reverend Rick Warren with a prominent role in his inauguration,” Frank said in a press release. “Religious leaders obviously have every right to speak out in opposition to anti-discrimination measures, even in the degrading terms that Rev. Warren has used with regard to same-sex marriage. But that does not confer upon them the right to a place of honor in the inauguration ceremony of a president whose stated commitment to LGBT rights won him the strong support of the great majority of those who support that cause.”

The Reverend Rick Warren is a best-selling author and heads the prominent evangelical Saddleback Church in Southern California.

Warren and Obama first met in 2006 at a Saddleback AIDS forum where the president-elect challenged him on preaching against contraception.

A prominent leader in the evangelical movement, Warren supports the outlawing of abortion in all cases and is a staunch gay rights opponent. But his moderate tone on AIDS, poverty and climate change have made him controversial among social conservatives.

Gay activists say Warren is homophobic. They point out that his Saddleback megachurch bans gays and lesbians from membership, he supports the controversial ex-gay movement that claims gays can be “cured” through prayer, and, most importantly, he supported the passage of Proposition 8 – the California constitutional amendment that yanked back the right of gay and lesbian couples from marrying in the state.

In that heated gay marriage debate, Warren likened gay marriage to an incestuous relationship, pedophilia and even polygamy.

“Mr. Warren compared same-sex couples to incest. I found that deeply offensive and unfair,” Rep. Frank said on Late Edition.

“If he was inviting the Rev. Warren to participate in a forum and to make a speech, that would be a good thing,” Frank said. “But being singled out to give the prayer at the inauguration is a high honor. It has traditionally given a mark of great respect. And, yes, I think it was wrong to single him out for this mark of respect.”

Rep. Frank is the first openly gay elected House member.