NEW YORK - Orthodox Jewish groups sued New York City on Thursday to try to block a new rule requiring parental consent for a circumcision ritual in which the circumciser uses his mouth to draw blood from the baby's penis.

The lawsuit, filed in US District Court, says the regulation is unconstitutional and violates religious freedom by targeting a Jewish ritual.

The rule, adopted unanimously by the New York City Board of Health last month, is aimed at reducing the risk that infants will contract herpes from the ancient ritual.

Using oral suction to take blood from the area of the circumcision wound is common in some of New York's ultra-Orthodox Jewish communities.

At least 11 boys caught herpes from the practice between 2004 and 2011, according to city health officials. Two of them died from the disease and two others suffered brain damage, they said.

Under the rule, parents must sign a consent form that says the health department advises that "direct oral suction should not be performed" because of the risk of contracting herpes.

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