There is nothing to study. Circumcision is bodily mutilation. Perpetuated by primitive people.
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source : http://www.citymed.co.nz/minor-surgeries/circumcision
And how many of them had a say in the matter? None.
People who self mutilate, or mutilate their children are primitive simpletons.
you clearly didn't check the source.
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TEENAGERS
Cultural reasons, particularly in the Polynesians, Phillipinos, Fijians
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REASONS FOR CIRCUMCISION:
Cultural Reasons
Some cultures strongly believe in circumcision, and circumcision is an integral part of their culture. Notably the Pacific Islanders in New Zealand have an almost 100% circumcision rate. The Pacific Islanders traditionally choose to have circumcision performed in late childhood or early puberty as a rite of passage to manhood.
I guess you can argue that even as a teenagers they don't really have a choice if they don't want to be seen as un-manly dude.
This is slightly off topic.