Lawyers for the city of San Francisco have suggested the proposed ban of circumcision for underage males contravenes the US constitution.
Their comments come after a challenge to the ban from an interfaith group of Muslims and Jews on the basis that Californian state law prohibits individual city lawmakers from placing limits on procedures by medical staff.
Russell Crowe has described circumcision as "barbaric and stupid" in a venom-filled online debate on the subject.
The Australian Oscar-winning actor, known for courting controversy in media interviews, wrote on his Twitter page that it was immoral to circumcise male infants and said he would "take attentive parenting over barbarism".
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.