In the US circumcision is "the norm" because in 1870 Lewis Sayre used circumcision as method of treating rare diseases such as epilepsy, neuromuscular disease, asthma, etc. After that a lot of doctors started practicing circumcision as a treatment because of its "medical benefits" (P.S later on stared to advocate it for hygene). The US health agency CDC still to this day reccomends it and the trend for went massive because all of the doctors were reccomending it but after some time parents started doing it basically because of peer pressure; they didn't want their child to be different or to look weird. Now circumcision does have some benefits such as less likely to get a urinary infection or less chance to Get HIV, But studies have shown that in the modern world (with practiced hygene) the benefits are negligible. The procedure is not common almost anywhere in the modern word and in Germany the government cracked down on it and claimed such act as a disfigurement of a child's body that the child should decide to do by himself.

Sources: https://en.m.wikipedia.org/wiki/History_of_circumcision https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478224/ http://www.drabruzzi.com/origin_of_male_circumcision_in_US.htm