According to Jewish sources, the history of circumcision indicates that the practice has gone through many changes. Orthodox rabbis have debated as to whether to perform just milah or to also perform periah. There have also been debates as to whether circumcision was valid if a metal knife was used instead of fingernails or flint. Circumcision causes babies intense pain and suffering. All three options are far safer than total foreskin amputation, which, of course, was invented by mortal rabbis and not by God.
Adults have plenty of unmyelinated nerves also.
Injecting the anesthetic into the genital area is painful for the baby. Once the anesthetic has taken effect, the baby's screaming from pain during the surgery is only reduced and by no means eliminated. It basically needs no care, no retraction, no nothing. No major scientific body has accepted these studies as proof that circumcisions prevent UTIs. In addition, contradictory studies also exist, showing no correlation between UTIs and circumcisions.