(CNN) -- New York City's plan to limit an ultra-Orthodox Jewish form of circumcision is the target of a lawsuit filed in federal District Court in Manhattan.
The regulation, passed in September by the city's Department of Health, requires all rabbis, called "mohels" in the context of the ritual, to get parental consent on a form stating that the procedure can lead to health risks.
The suit, filed by several Jewish groups and three rabbis on October 4, argues that "the government cannot compel the transmission of messages that the speaker does not want to express -- especially when the speaker is operating in an area of heightened First Amendment protection, such as a religious ritual."
In the ritual, known as metzitzah b'peh, after removing the foreskin of the penis the mohel places his mouth briefly over the wound, sucking a small amount of blood out and discarding it. Antibacterial ointment is applied and the wound is bandaged.
The Health Department says the procedure is dangerous because the contact with the mouth could transmit diseases such as herpes. Earlier this year, health officials reported 11 babies who underwent the procedure had contracted herpes infections between 2000 and 2011, and two had died.
The health department reported that an estimated 20,493 infants in New York City were exposed to direct oral suction in that period.
"The city's highest obligation is to protect its children; therefore, it is important that parents know the risks associated with the practice," said Dr. Thomas A. Farley, commissioner of the city's health department, in a news release. "The Health Department's written consent requirement is lawful, appropriate and necessary."
"The government is overstepping its boundaries," said Rabbi Levi Y. Heber of International Bris Association, one of the organizations filing suit. "Freedom of religion and speech is at stake here. The fact the health department is concerned when experts have come out with affidavits on these risks, it's all assumptions. They're just trying to regulate a ritual."
Heber said they feel it best to get the truth out and challenge the regulation in court. He said the study is based only on assumptions, regardless of the statistics.
"Over 90% of those cases don't have anything to do with Jewish tradition," Heber said.
Some anti-circumcision groups, however, say the lawsuit's argument for religious liberty is just an excuse to defend old tradition that some frown upon as strange compared with mainstream hospital circumcisions.
"Why are the groups filing suit so afraid of the consent form?" said Georganne Chapin, executive director of Intact America. "With any social change, as any custom starts to change or die out it looks more strange."
Chapin opposes the health department's consent form, saying it cannot validate a procedure that violates a child's rights.
"No amount of information you put in that form makes it valid," she said. "... To say that if a parent signs a consent form, only slice off the penis and suck the blood, that's an extremely corrupt position for the city to take. Terrible ethics. I think it's rather fascinating that ... the city has given a pass to criminal action."
Another rabbi involved in the lawsuit contends more sensible precautions should be taken.
"The city is entitled to enforce whatever rules it enacts, of course," said Rabbi Avi Shafran, who is director of public affairs for Agudath Israel of America. "But we feel that this rule is unfair, uncalled for, and in violation of the religious rights of citizens.