How is circumcision practiced in Judaism Christianity and Islam?

Answer 1

Jewish boys are circumcised (at 8 days old or later, if heath reasons require a delay) as a sign of the covenant between G-d and Jewish men. All major branches of Judaism require male circumcision. Jewish circumcision has nothing to do with cleanliness.

Muslim men are circumcised for cleanliness reasons. Islam believes that an uncircumcised man can't be completely clean at all times.

Christianity does not require circumcision, though some cultures routinely circumcise, often at age 13, such as Filipinos.

Non religious circumcision is generally done for health reasons, though this is a highly debatable subject, and increasingly frowned upon. There is a small number of non-religious Jews that do not advocate circumcision, however this is contrary to Jewish practice. Furthermore, no such anti-circumcision movement exists among Muslims, except perhaps, among those who have left the faith.