Re: What were your medical reasons for circumcising?
I was uncircumcised at birth and was later circumcised due to complications. I know your looking for the medical benefits but I have to suggest insight into the statistics quoted here. I had to look into cancer.gov because I've never looked into that specific source.
Circumcision is also found to reduce prostate cancer but, as with penile cancer, this is prior to the first act of intercourse. I feel if you want to give this medical procedure as an option it would be better to wait, since you should have time to ask your son what he would want prior to him having sex and allow him to make this choice for himself.
When it comes to UTI's there is a reduction during the first six months of life, however sanitary living conditions and proper hygiene protect just as much. The increased rate in uncircumcised men is due to the fact that there are more places for bacteria to hide, however if there is no bacteria there to begin with this is a moot point.
Circumcision has also been found to reduce the rate of certain STD's specifically HSV-2 and HPV. Once again, however, safe sex education can keep this number at zero whether circumcised or uncircumcised.