Circumcision is a safe and effective procedure. It reduces invasive penile cancers, UTI's, STD's, HPV, general infections, and HIV to varying degrees. It's a one time procedure that costs very little and doesn't affect sensitivity, sensation, or sexual performance. Anesthesia isn't always used, though it should be and it can always be requested; anesthesia is used in most circumcisions performed by medical professionals, so it is not a painful procedure. Furthermore, it isn't traumatic by definition since it has no lasting physical or psychological damage.
The science is in on circumcision. It isn't the barbaric practice a vocal minority on the Internet says it is. In fact, it literally saves lives, particularly in developing nations. This is why the WHO, UNAIDS, the AAP, the AMA, the CDC, the Bill and Melinda Gates Foundation, and a dozen and a half African health ministries support it in one form or another. (In fact, no major health organizations support outlawing circumcision since doing so would lead to the procedure being done illegally and unsafely.) Millions of boys and men have been circumcised across Africa in recent years in large thanks to the Bill and Melinda Gates Foundation. It would, however, be better if they focused on infant circumcision since that leads to far fewer complications (which are incredibly low in infants, mostly being minor bleeding).
The last refuge of circumcision opponents is what pervades most of this thread and the websites specifically set up to cherry pick science journals: the argument from bodily autonomy. This is the argument which says it is wrong to permanently alter a person's body without his consent unless the alteration is medically necessary. This argument is usually applied inconsistently. Circumcision certainly isn't medically necessary. A person can live a happy, healthy life without it. Just the same, vaccination is not medically necessary - it's preventative. People have and do live happy, healthy lives without them. That isn't to say they aren't great. They are. Everyone should get all the basic vaccines as well as annual flu vaccines. But being highly effective and saving lives does not qualify something as medically necessary. An aspirin a day will reduce various heart risks. That doesn't make them medically necessary. So, both circumcision and vaccination are preventative measures, but neither is medically necessary. Both also cause permanent change - circumcision removes foreskin while vaccines add antibodies. Unless we want to simply play with some red herrings and abandon the argument from bodily autonomy, then circumcision and vaccination violate bodily autonomy. But no reasonable person is against vaccination. Why is circumcision different? The foreskin has no apparent function, its removal doesn't have an impact on sensitivity, sensation, or sexual performance, and circumcised men are less prone to a host of diseases. If I have a son, I can't imagine not having him circumcised.
This link shows that complications are rare.
http://newborns.stanford.edu/CircComplications.html#death
This peer reviewed meta-analysis concludes that circumcision doesn't impact sensitivity, sensation, or sexual performance.
http://www.ncbi.nlm.nih.gov/pubmed/23749001
Here is the body of observational evidence that existed in support of circumcision prior to the three oft-cited African studies.
http://www.ncbi.nlm.nih.gov/pubmed/12917962
Here are those African studies that conclude circumcision reduces female-to-male HIV transmission by 60%.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1262556/
http://www.ncbi.nlm.nih.gov/pubmed/17321310
http://www.ncbi.nlm.nih.gov/pubmed/17321311
If you Google "cdc circumcision pdf", you will find a link that explains that circumcision reduces a host of diseases and cancers. (I'm on mobile and can't seem to get the link directly.)
Here is a link referencing the partnership between the Bill and Melinda Gates Foundation and a host of African health ministries in getting more boys and men circumcised.