Also what are the different religious beliefs on circumcision?

Different. Jews and muslims are for it, because torah and koran support it. Christianity and other religions (major ones) don't support for religious purposes. I am not sure about some "minor" cults, though.
Muslims & Jews. Circumcision is part of jewish & muslim religions. Jewish boys need to be circumcised on 8th day of life, ceremony is called a bris and performed by a mohel or religious circumciser. A number of fundamentalist baptists follow similar tradition. Muslims undergo circumcision but is performed at different ages in different countries. Some in infancy, age 5 - 9 years in turkey. Was done bc in egypt.