When Jewish parents have their boys ritually circumcised on their eighth day of life, they may be getting something they didn't expect: herpes, according to a group of researchers in Israel and Canada. After the field of medicine caught on to how diseases are transmitted in the 19th century, most rabbis changed their advice to allow the mohel (circumciser) to suck blood off the boy using a medical instrument rather than the mouth, as was traditionally done. But a few mohels continue the old practice.

What the researchers wanted to know: Can ritual circumcision with oral suction transmit herpes?

What they did: The researchers studied the cases of eight boys who developed genital infections with HSV-1, a herpes virus, after circumcision.

What they found: All eight boys had mohels who had done oral suction, which is so rare that it's unlikely to be a coincidence. Two patients had their circumcisions by the same mohel five years apart, and two others by another mohel. The researchers were able to test four of the mohels who had circumcised the boys; blood tests showed all four been exposed to HSV. Most of the mothers had not been exposed to the virus, which is the usual source of children's infections.

What the study means to you: The authors say the Talmud doesn't specifically require oral suctioning, and most rabbis agree.

Caveats: This isn't absolute proof, but it seems pretty likely the infections came from the mohels.

Find out more: The bris, from Torah.org

Read the article: Gesundheit, B., et al. "Neonatal Genital Herpes Simplex Virus Type 1 Infection After Jewish Ritual Circumcision: Modern Medicine and Religious Tradition." Pediatrics. August 2004, Vol. 114, No. 2, pp. e259–e263.

Abstract online: http://pediatrics.aappublications.org