Circumcision gained popularity in the US during WWII. American soldiers were circumcised in a bid to prevent "venereal disease."
Then they came home and when they had sons of their own felt a strange need that son should look like Daddy, so circumcised them and it became popular for several decades.
Finally it was figured out that circumcision wasn't really all that effective at preventing sexually transmitted infections, but the trend was to cut.
It is slowly getting less popular in the US, but there is still a lot of talk about people being worried that son would look different than daddy which I really don't understand.
When my son was little and brought this up, my husband just told him the truth, "The doctor cut the end off when I was a baby." Son felt bad for his dad that he had a bad doctor that would do something like that! Easy peasy.