Circumcision has been done routinely in hospitals with changing reasons.  At one point in American history, doctors thought it prevented masturbation which they thought caused health problems (a suggestion also made by prominent medieval Jewish scholar and doctor Maimonides, though it was never the primary reason for Jewish circumcision).  This hasn’t been a compelling argument for quite a while, for obvious reasons.  Another long-standing argument on the pro side is about hygiene, which as it turns out can be achieved in uncircumcised boys and men with - you guessed it - proper hygiene.  
On the list of more credible current medical claims, there is evidence to support a small reduction in rates of urinary tract infections, a reduction in the (already extremely low) rate of penile cancer, and a reduction in the rate of transmission of HIV and HPV - which though it is significant, is not nearly as significant as safe sex, which works equally well for both circumcised and uncircumcised men.  Of course, there are also risks, as with any surgery, of infection or excess bleeding, though the rates are low.  Familydoctor.org provides a brief run-down of risks and benefits, and for a more extensive discussion, see circs.org.