By Pauline Kim, CNN

New York (CNN)– A controversial Jewish circumcision ritual is under fire after allegedly causing the deaths of two infants and exposing potentially thousands more to the risk of herpes infections.

New York City health officials are pushing a proposed regulation that would require parents to sign a consent waiver before they take part in a circumcision ritual called "metzitzah b'peh," typically practiced by ultra-Orthodox Jews. The ritual potentially poses a fatal risk to newborns, according to the New York City Department of Health and Mental Hygiene.

The legislation was proposed at a Board of Health meeting last month by Dr. Jay K. Varma, deputy commissioner for disease control for New York City's health department, after 11 infants contracted neonatal herpes between November 2000 and December 2011, after the circumcision ritual. Two of the infants died.

Jews regularly practice circumcision as part of their religion, but mostly ultra-Orthodox Jews practice metzitzah b'peh, during which the mohel, or person performing the procedure, orally sucks the blood from the infant's newly circumcised penis.

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The numbers reported came to light as the city's health department launched an investigation after the infant deaths were reported in New York, the most recent in September in Brooklyn.

The health department reported last month that an estimated 20,493 infants in New York City were exposed to direct oral suction. Baby boys who were reportedly circumcised "with confirmed or probable orogenital suction" between April 2006 and December 2011 had an estimated risk of contracting neonatal herpes (HSV-1) infection of 24.4 per 100,000 cases, making the risk 3.4 times greater than those infants who did not have direct oral suction, according to the health department findings.

In a statement advising New York parents to refrain from direct oral-genital suction during circumcision, New York City Health Commissioner Dr. Thomas Farley said, "There is no safe way to perform oral suction on any open wound in a newborn.

"Parents considering ritual circumcision need to know that circumcision should only be performed under sterile conditions, like any other procedures that create open cuts, whether by mohelim or medical professionals."

Reports of infant herpes infections and deaths are not new.

In November of 2004, the Department of Health reported that twin male infants contracted neonatal herpes after the ritual circumcision, one of whom died.

Spokesman Jerry Schmetter of the Brooklyn Defense Attorney's office said a criminal investigation regarding a rabbi who was linked to infant herpes cases, was "still ongoing."

In the case of the Brooklyn infant's death in September, the parents of the baby refused to tell authorities who performed the ritual.

The United Jewish Organizations of Williamsburg in Brooklyn could not be reached for comment.

Jeffrey Mazlin, a certified mohel and physician in New York who regularly practices circumcision procedures, said "only the more orthodox, the more traditional mohels" perform the metzitzah b'peh.

"[Orthodox Jews] look at it in terms of religion being more important than the individual, whereas someone who is more liberal will make sure that the individual's rights are taken care of," he said.

But the ritual is not just an upholding of a Jewish tradition, but also a firm reminder of their beliefs.

"Because blood is the life-giving element, they believe that it's supposed to be part of the whole procedure," Mazlin said.

The little blood that is drawn from the newly circumcised penis is usually left alone or wiped away under regular procedures, he said.

"There are no known medical benefits to sucking [the blood]," he said.

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Rabbi Moshe Tendler, professor of Talmudic Law and Bioethics at Yeshiva University, dismissed any defense of the practice, calling it "primitive nonsense."

"[The ritual] has nothing to do with religion. It's only their customs. But they've managed to convince the city that it's a violation of their religious freedoms."

Tendler notes that there is an alternative to the metzitzah b'peh in which a mohel doesn't use his mouth directly, but uses a sterilized glass tube or pipette to suck the blood from the wound, which many modern orthodox Jews have started to incorporate during their circumcision rituals.

The Jewish tradition of circumcision rituals originate from Scripture, in which God tells Abraham that all men must be circumcised eight days after they are born.

"Hundreds of years ago, they didn't know that you can get an infection by sucking the blood. So they were not concerned," said professor Arthur Hyman of Yeshiva University.

Dr. Daniel S. Berman, an infectious disease specialist, has defended the practice, arguing in a paper published in the Jewish journal Dialogue that there is still no evidence that metzitzah b'peh directly caused any of the reported infant herpes infections.

Berman even attributes racial bias in the New York City government as the reason behind the proposed mandate for the parent consent waiver.

Berman's opinion does not appear to be representative of the larger medical community. He could not be reached for comment Friday by CNN.

The Jewish Community Relations Council of New York could not be reached for comment.

Last week, a court in Germany outlawed circumcision on infants with the exception of medical purposes.

The ruling came after the case of a Muslim couple whose 4-year-old son was hospitalized after a circumcision procedure.

The Department of Health is accepting public comments on the proposed regulation until a public hearing July 23. At the hearing, there will be a public forum where the board will consider all comments and make a final vote September 13.