So the origins of circumcision isn't actually 100% known, and there is a lot of debate among scholars as to its purpose. This ranges from a rite of passage into adulthood, to reduce sexual pleasure, hygiene reasons, as a mark of humiliation, as a mark of wealth and many more. It's likely it was all of these to different people/cultures.
I do understand how it has cultural relevance, and how it can be difficult to break those social norms. However, throwing words like 'barbaric' and 'mutilation' to one side (as I dont think those will get us anywhere), you cannot deny that this is a big decision for any parent as whether you deem it culturally relevant or not, it is an un-necessary medical procedure. There is no denying that fact. And as with all medical procedures, it carries risk and pain.
To inflict that on someon who has no choice, and very little ability to voice their discomfort after the event, is rather questionable. It begs the question as to why you cannot allow your son to become educated on the practice and decide himself. Is it because you are afraid he will say no?
As to the religious relevance, while they may be culturally relevant now, the original reasoning for them has dissipated. Almost all of the original commandments given in the Old Testament (which is used in Judaism too as the Torah) were for the protection and welfare of the group, such as not eating shellfish and pork. This was simply because they were exceedingly hard to keep fresh and cook properly before refrigeration and thus the most likely to make the consumer ill. Similarly, the cleanliness issue is no longer a reason for circumcision.
There will always be horror stories surrounding procedures, just as there will always be a few lucky ones who walk out unscathed. But I do think that when it comes to a child, why take an unnecessary risk physically and psychologically when the child can make their own decisions later.