The nation’s largest Catholic civil rights group urged a national boycott of Miller Brewing Co. Thursday for its sponsorship of a San Francisco street fair.

The Catholic League is upset over Miller's ties to a fair promoted in an ad that shows semi-nude men and women in bondage at a table with sex toys portraying Leonardo da Vinci's "The Last Supper" painting.

"Miller is sponsoring an incredibly outrageous and palpably anti-Christian event," said Bill Donohue, president of the Catholic League.

The 2007 Folsom Street Fair, which organizers promote as "fairgrounds filled with people in their most outrageous leather/rubber/fetish attire" is planned for Sunday on Folsom Street in San Francisco.

The fair will benefit a group of local charities, including an organization called the Sisters of Perpetual Indulgence, who call themselves "queer nuns."

"Want to put your cute leather outfit to good use and serve the community at the same time?" according to a promotion on the group's Web site.

Miller wants its logo removed from the poster, according to a statement in the New York Sun.

"While Miller has supported the Folsom Street Fair for several years, we take exception to the poster the organizing committee developed this year. We understand some individuals may find the imagery offensive," said Julian Green, a Miller spokeswoman in a statement.

Click here to read a report in the New York Sun.

Donohue called Miller's response a "lame statement of regret."

"Miller leaves us with no options," Donohue said.

Father Jonathan Morris, a Roman Catholic priest based in Rome, said the group is not nuns and wants to promote gay rights.

"What they are doing is trying to make a mockery of religion," Morris, a FOX News analyst, said.

Morris called the ad "blasphemy."

"When you take something that is sacred to somebody, you turn it into the profane and you use it for your own good," Morris said. "That's bad for society."