Circumcision
Circumcision is very important to most branches of Judaism, with over 90% of male adherents having the procedure performed as a religious obligation. The basis for its observance is found in the Torah of the Hebrew Bible, in Genesis chapter 17, in which a covenant of circumcision is made with Abraham and his descendants. Jewish circumcision is part of the "brit milah" ritual, to be performed by a specialist ritual circumciser, a "mohel", on the eighth day of a newborn son's life, with certain exceptions for poor health. Jewish law requires that the circumcision leaves the glans bare when the penis is flaccid. Converts to Conservative and Orthodox Judaism must also be circumcised; those who are already circumcised undergo a symbolic circumcision ritual. Circumcision is not required by Judaism for one to be considered Jewish, but some adherents foresee serious negative spiritual consequences if it is neglected.
Circumcision controversies
Dr. John Harvey Kellogg recommended circumcision of boys caught masturbating, writing: "A remedy for masturbation which is almost always successful in small boys is circumcision, especially when there is any degree of phimosis. The operation should be performed by a surgeon without administering anaesthetic, as the pain attending the operation will have a salutary effect upon the mind, especially if it be connected with the idea of punishment." But he was opposed to routine circumcision of infants: "It is doubtful, however, whether as much harm as good does not result from circumcision, since it has been shown by extensive observation among the Jews that very great contraction of the meatus, or external orifice of the urethra, is exceedingly common among them, being undoubtedly the result of the prolonged irritation and subsequent cicatricial contraction resulting from circumcision in infancy."