some previous threads on the same subject:
https://www.reddit.com/r/AskHistorians/comments/18k4ex/how_did_medical_circumcision_of_male_infants/
https://www.reddit.com/r/AskHistorians/comments/y5j29/why_did_circumcision_catch_on_in_places_like_the/
https://www.reddit.com/r/AskHistorians/comments/1hscjr/how_did_circumcision_grow_from_a_practice_of/