During the late nineteenth and early twentieth centuries there were two views on the relationship between syphilis and male circumcision: one was that circumcision provided protection against syphilis, another that circumcision was itself a significant source of syphilitic infection. This article reviews this debate, relates the first view to an influential article by Jonathan Hutchinson in 1855 and considers the subsequent use made of his statistics. It is suggested that the original statistics were of dubious value and that the promise of protection against syphilis was an additional argument for doctors who were keen to introduce universal circumcision of male infants for other reasons, the most significant of which was related to the conviction that it would discourage masturbation. The article further considers the controversy over whether Jews were healthier than other peoples, and the interaction among medical, moral, and customary/religious reasons for circumcising boys, and concludes that, while the operation never played any role in the control of syphilis, circumcision was indeed a significant cause of illness and death among male infants before the standardization of aseptic operating techniques.