On March 29, 2017, the mayor of New York, Bill de Blasio, admitted defeat. “We tried a new policy,” he said. “It didn’t work, which I’m very unhappy about.” During the previous two years, six newborns in New York City had suffered severe infections with herpes simplex virus (HSV)—a situation de Blasio had been hoping to avoid.

Adults infected with HSV typically develop ulcers in their mouth or blisters in their anal and genital areas. For newborns, however, it’s a different story. In babies, HSV can enter the bloodstream and infect the liver (causing hepatitis) or the lungs (causing pneumonia) or the brain (causing encephalitis). Unlike first-time infections in adults or older children, newborn HSV infections can cause permanent brain damage or death. Typically, newborns come in contact with HSV when they pass through the birth canal of a mother who is infected. However, none of the six infants who were infected with HSV in New York City got it from their mothers. So where did they get it?

In the Bible’s Genesis 17:10-11, God made a deal with Abraham, the father of the Jewish people: “Every manchild among you shall be circumcised. And ye shall circumcise the flesh of your foreskin, and it shall be a token of a covenant between me and you.” Of all the mitzvahs (or good deeds) mentioned in the Torah, circumcision—a sacred covenant between God and every Jewish male—is second only to “Be fruitful and multiply.” Unfortunately, this practice, which is at least 4,000 years old, has a darker side.

On Sept. 12, 2012, Sharon Otterman, a reporter for The New York Times, watched Romi Cohen perform a circumcision. “The mohel lifted the infant’s clothing to expose his tiny penis,” she wrote. “With a rapid flick of a sharp, two-sided scalpel, the mohel sliced off the foreskin and held it between his fingers. Then he took a sip of red wine from a cup and bent his head. He placed his lips below the cut, around the base of the baby’s penis, for a split second, creating suction, then let the wine spill from his mouth out over the wound.” In other words, Cohen used his mouth to remove blood from the circumcision site.

The ritual, which is called metzitzah b’peh (sucking with the mouth), dates back to the Babylonian Talmud written in the fifth century A.D. Because there is no safe way to clean an open wound with your mouth, most rabbinical authorities have suggested using a sterile pipette for this “suctioning,” or sterile gauze.

Unfortunately, ultra-Orthodox Jewish communities in New York City and Lakewood, New Jersey, have continued to perform the metzitzah ritual, which is what had caused those recent HSV infections in New York City. It wasn’t the first time that this problem had come to public attention.

Between 2004 and 2012, 13 babies in New York City contracted HSV during the metzitzah ritual; two of the 13 died and two suffered permanent brain damage. During that period, health officials estimated that the ritual was performed on about 3,600 babies in their city every year. In response, the mayor of New York, Michael Bloomberg, took action. Bloomberg required mohels who performed metzitzah to provide a health department pamphlet to parents describing the risks of HSV as well as to obtain written consent acknowledging those risks. Mohels who refused to comply would be sent a warning letter and fined as much as $2,000.

Bloomberg’s plan had the support of most of the mainstream Jewish community. Rabbi Gerald Skolnik, president of the Rabbinical Assembly, said the procedure was “inconsistent with the Jewish tradition’s pre-eminent concern with human life and health.” Rabbi Moshe Tendler, a professor of Talmudic law and bioethics at Yeshiva University, took Rabbi Skolnik’s assessment one step further, calling the metzitzah ritual “primitive nonsense.” “The ritual has nothing to do with religion,” he said. Even in Israel, the practice of metzitzah has been abandoned; in 2002, the Chief Rabbinate declared that blood from a circumcision should be removed with a sterile pipette.

During the democratic primary for mayor of New York, Bill de Blasio said that in order to retain the “trust” of that community, he planned to overturn Bloomberg’s law. When de Blasio became mayor, he entered into a handshake agreement with ultra-Orthodox Jewish leaders that any mohel who had transmitted HSV to a newborn during the metzitzah ritual could never perform another circumcision again. Unfortunately, de Blasio’s honor system wasn’t working. When six more HSV cases from the previous two years popped up, he revised his ruling. The two mohels who were found to have transmitted HSV to infants were prohibited from performing more circumcisions. If these mohels ignored the warning, they could be fined up to $2,000.

Although the New York City Health Department has now begun to identify mohels who are shedding HSV from their mouths, their names are confidential. So it falls to the parents to determine whether their newborns might be at risk. “Ask the mohel if they are infected with herpes,” advised de Blasio, “and if they are, you should find a different mohel.”

The time has come for New York City officials to abandon their ineffective, slap-on-the-wrist punishment for mohels who put babies at unnecessary risk of a potentially lethal infection. The only reasonable way to protect newborns is to ban the metzitzah ritual, criminally charging both the mohels who perform the procedure and the parents who allow it with child neglect. For several reasons, this is the only course of action that makes sense. First, about 70 percent of all adults have been infected HSV. Second, most adults will shed HSV from their mouths unknowingly. In other words, it’s hard to predict which babies are at risk. Third, rinsing the mouth out with wine—as Romi Cohen had done—does not effectively kill HSV. Fourth, De Blasio’s edict that mohels who infect a child with HSV should no longer be allowed to perform the metzitzah ritual is at best shortsighted. In essence, de Blasio is saying that mohels are allowed to permanently harm or kill one child without consequence.

Yet despite the furor surrounding the recent spate of newborn HSV infections in New York, Mayor de Blasio has said, “We have to be mindful of religious freedom.”

While it is reasonable to allow adults to martyr themselves to their religion, it is not reasonable to allow them to martyr their children. The job of government officials is to protect these children from such obvious abuses. When Bill de Blasio said during his primary that he needed to maintain the trust of the ultra-Orthodox Jewish community, it would have been more accurate if he had said the “voting community,” because children don’t vote. If they did, I suspect they wouldn’t sign up for a ritual that could cause them to suffer permanent brain damage or end their life before it had begun.

Paul A. Offit is a professor of pediatrics at the University of Pennsylvania Perelman School of Medicine, the co-director of CHILD USA, and the author of Bad Faith: When Religious Belief Undermines Modern Medicine (Basic Books, 2015).