In the end, it was a battle that even Foreskin Man could not win.

Nearly nine months after campaigners in San Francisco launched a bid to make the circumcision of males under the age of 18 illegal, a judge ordered the measure to be removed from a public vote.

San Francisco residents had been set to vote on a ban in November, after the controversial proposal attracted more than the minimum 7,168 signatures required by the city for initiatives to be added to a public ballot.

If it had been successful, the proposal would have made it a "misdemeanour to circumcise, excise, cut or mutilate the foreskin, testicle or penis of another person who has not attained the age of 18".

There was to be no exemption for religious Jewish or Muslim ceremonies, and those who breached the rules would have faced up to a year in jail or a £6,100 fine.

A broad coalition, including Jewish and Muslim groups and medical professionals, vowed to fight the proposal, spurred on when it emerged that one of the leading anti-circumcision campaigners was behind a comic book featuring a Monster Mohel, an Aryan superhero and other characters labelled "antisemitic" by the Anti-Defamation League (ADL).

Campaigners also compared male circumcision to female genital mutilation, which is banned by the US federal government.

A similar proposal was dropped in nearby Santa Monica because one of the main campaigners objected to religion being brought into the debate.

In San Francisco, those opposed to the ban began legal proceedings in June calling for the measure to be scrapped from the ballot.

This week they celebrated a victory when Superior Court Judge Loretta Giorgi ruled that the measure would be "expressly pre-empted" because under Californian state law cities cannot regulate medical practice.

She said that evidence showed that circumcision was "a widely practised medical procedure" and therefore could not be limited, although she also acknowledged there was a "legitimate debate" to be had on the issue.

She also said a ban would violate the constitutionally protected right to freedom of religion, because circumcision is part of both Jewish and Muslim worship.

Her decision was praised by Jewish groups. "It is up to parents to make the choice whether or not to have their baby boys circumcised," said Abby Michelson Porth, of the Jewish Community Relations Council.

The ADL welcomed it as "a critical affirmation of religious freedom and parental rights". Nancy Appel, the ADL's associate regional director, said: "The Court has rightly upheld the freedom for Jews and Muslims in San Francisco to choose to circumcise their children in accordance with long-standing religious tradition."

She also said she was heartened by the judge's decision not to accept the comparison with female genital mutilation.

Supporters of the ban said they were considering an appeal. "We will not stop until all men are protected from this damaging and harmful surgery," said lead activist Lloyd Schofield.