A proposal to ban the circumcision of male children in San Francisco has been cleared to appear on the November ballot, setting the stage for the nation's first public vote on what has long been considered a private family matter.

But even in a city with a long-held reputation for pushing boundaries, the measure is drawing heavy fire. Opponents are lining up against it, saying a ban on a religious rite considered sacred by Jews and Muslims is a blatant violation of constitutional rights.

Lloyd Schofield, a proponent of a ballot measure that would ban the circumcision of males under 18, poses for a photograph at City Hall in San Francisco, Wednesday. Jeff Chiu/Associated PressElections officials confirmed Wednesday the initiative had qualified for the ballot with more than 7,700 valid signatures from city residents. Initiatives must have at least 7,168 names to qualify.

If the measure passes, circumcision would be prohibited among males under the age of 18. The practice would become a misdemeanour offence punishable by a fine of up to $1,000 or up to one year in jail. There would be no religious exemptions.

The proposed ban appears to be the first in the country to make it this far, though a larger national debate over the health benefits of circumcision has been going on for many years. Banning circumcision would almost certainly prompt a flurry of legal challenges alleging violations of the First Amendment's guarantee of the freedom to exercise one's religious beliefs.

Supporters of the ban say male circumcision is a form of genital mutilation that is unnecessary, extremely painful and even dangerous. They say parents should not be able to force the decision on their young child.

"Parents are really guardians, and guardians have to do what's in the best interest of the child. It's his body. It's his choice," said Lloyd Schofield, the measure's lead proponent and a longtime San Francisco resident. He added the cutting away of the foreskin from the penis is a more invasive medical procedure than many new parents or childless individuals realize.

But opponents say such claims are alarmingly misleading, and call the proposal a clear violation of constitutionally protected religious freedoms.

"For a city that's renowned for being progressive and open-minded, to even have to consider such an intolerant proposition ... it sets a dangerous precedent for all cities and states," said Rabbi Gil Yosef Leeds of Berkeley. Leeds is a certified "mohel," the person who traditionally performs ritual circumcisions in the Jewish faith.

Jews consider religious male circumcision a commandment from God. It also is widely practised by Muslims. Most Christian denominations neither require nor forbid circumcision.

Schofield's group calls its initiative the San Francisco Male Genital Mutilation bill, though he said the city attorney has opted to call the measure "Male Circumcision" on the ballot. The group's official website features a picture of a wide-eyed, delighted-looking baby and urges visitors to help "protect ALL infants and children in San Francisco from the pain and harm caused by forced genital cutting."

International health organizations have promoted circumcision as an important strategy for reducing the spread of the AIDS virus. That's based on studies that showed it can prevent AIDS among heterosexual men in Africa.

But there hasn't been the same kind of push for circumcision in the U.S., in part because nearly 80 per cent of American men are already circumcised, a much higher proportion than the worldwide average of 30 per cent. Also, HIV spreads mainly among gay men in the U.S., and research indicates circumcision doesn't protect gay men from HIV.