This can be a very heated debate between people. For proponents there exist several agurment besides heelth benefits, mostly to do with social norms, cultrual and religious tradition and what other males in the family have had done.
Personally I'm against circumcision for many reasons. I'll try my best to briefly describe them and stick to the main points.
a) the proposed health benefits are quite over-stated.
The argument that cleaning is easier and infections are avoided might carry some weight in parts of the world where running water, soap, general sanitation etc aren't readily available, but in countries like the US I find it to be pretty weak.
If one looks at the severity of the possible infection one might get and the actual numbers involved, not just percentages of chance, it becomes rather clear that amputating a part of your penis is overkill.
I'm intact, and I've never encountered any problems or discomfort that I can recall being anywhere near as memorable as say a throat or ear infection, and I certainly wouldn't advocate remove parts of either just to avoid a blocked ear for 2 days.
If anything, the instances of complications arising out of botched circumcisions seems to outnumber both the numbers and in many cases exceeds the severity of the majority or problems a foreskin can cause.
I had a a friend who suffered from phimosis, a condition that makes the foreskin tight and non-rectractable, and he was cured with a simple cream that he had to apply twice daily for 5 days. No surgery was needed, and in developed countries this form of medicine is cheap and readily available, making circumcision a case of cutting of a foot to cure an ingrowing toenail.
Much has been said about the HIV transmition rate being double for those uncut, but there's very little emperical evidence to support this, and the numbers of HIV and AIDS cases in the US and Europe don't support it either. The US is the most heavily circumcised developed country in the world, yet also has the highest instances of HIV contraction among non-drug related cases. In Europe on the other hand, where circumcision is extremely rare outside of the Jewish and Muslim populations, the insatnces are very fewer. This illustrates that the best prevention is a condom, and telling people that they are better protected against HIV by being circumcised actually puts them at greater risk because they felsely believe they need not take any precaution and so are at even greater risk. Kinda shooting themselves in the foot with that one.
b) I find it to be a Human Rights issue
There's no easy way to say this without upsetting different groups of people, but I firmly believe on'es own body is entirely their own and no one, not even parents, should have the right to alter it for aesthetic, cultural or religious purposes. Unless a child requires a circumcision to cure an ailment which can't be cured in any other way, I think it's wrong, and several European countries are now banning neo-natal circumcision that is not an absolute medical necessity.
I have friends and extended family that are Jewish, and we have discussed this a few times. I udnerstand being Jewish in the religious sense requires one to be circumcised, but there has to come a point where religion cannot dictate another person's right over their own body. Raise a child in your faith, tell him about the ritual and when he is old enough to udnerstand the physical ramifications of the procedure let him decide for himself. I've met Jewish people who have said they won't circumcise their child and don't think of any other Jews as 'less Jewish' if they aren't circumcised either.
c) there exist certain drawbacks
The removal of the foreskin also removes multiple nerve endings and sensation one gets during sex and masturbation. I've met people who had the operation done later in life and agree that after it heals they tend to feel a lot less sensation, not that it stops them from enjoying sex or achievng orgasm obviously, but it does make a noticable difference.
To me, ANY lessening of the pleasure of sex and self-gratification MUST be a personal choice and not one forced upon you at an age you can't consent.
d) the historicity behind circumcision
Circumcision can be dated as far back as the Egyptians, who performed it as a ritual because they believed that like a snake shedding it's skin, 'shedding' your foreskin made you stronger. This of course isn't the case.
Jews performed it as a rite of passage and cultural identification for their kinship, much like a tatoo, as was madated by the Bible. Being a religious act, I think people should decide for themselves whether or not they want to be part of the religion and if they agree that this action is necessary.
During the early 20th century in the US, Kellog (that guy from the cereals) came up with circumcision as a means to prevent all sort of ailments in young boys, inclduing and not limited to madness and blindness, and the purpose of it was to prevent boys from masturbating as this was seen as the cause of a wide array of health issues, not to mention a big social no-no, and with the removal of the foreskin, it becomes harder for one to masturbate as often as with one, ergo cutting down on what was thought to be a dangerous behavior. Again, we know now that mastrubation isn't only safe, it's actually a healthy thing.
Anyway, there's tons more to be said on the subject, both in favor of and against the practise, I just thought I'd try to briefly give my main points of 'contention' on the issue. Hopefully this won't start a fight, and we can have a discussion without people resorting to personal attacks and various other non-constructive argumentation.