A San Francisco-wide ban on the circumcision of males under the age of 18 has moved a step closer to reality after sufficient residents signed a petition to get the issue on the agenda for a vote in November.

The controversial proposal, first outlined last November, has now attracted more than 7,168 signatures – the minimum required by the city for initiatives to be added on to a public ballot.

The measure would make 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."

Under the terms of the proposal, circumcision would be prohibited even in religious Jewish or Muslim ceremonies. Those who continued the practice would face up to a year in jail or a £6,100 fine.

However, should San Franciscans vote in favour in November, there are likely to be legal challenges from individuals and religious organisations on the grounds of the ban being unconstitutional and breaching the First Amendment right to religious freedom.

Lloyd Schofield, the activist behind the plans, said he believed the debate on circumcision "was a conversation that needed to happen". He has compared it to tattooing a child and called it "genital mutilation".

Rabbi Gil Yosef Leeds, a mohel from Berkeley in San Francisco, said that even considering such a plan was a worrying sign.

He said: "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."

The Agudath Israel of America organisation called the proposal "an unprecedented assault on Americans' freedom of religion".

"The San Francisco proposal should be roundly and soundly defeated by a large majority of that city's voters, who cherish liberty and its protection," they said. "We trust that such will happen."