All babies who are circumcised ARE affected by it in later life.
Source please
Source = common sense. Having something that serves a clear purpose (or will in later life) and having it taken from you without your having any say in the matter will obviously affect your life. This is manifest whether it's a foreskin, a hand, the default right to a driving licence, the right to marry, a trust fund etc.
If you are querying the extent to which a person will be affected by a circumcision, again common sense dictates that permanently losing thousands of nerve-endings means that a great deal of sensation will never be enjoyed.
As somebody with severe neuropathy throughout my body, which began after I had become an adult, I know very well what the negative effects are when nerves die and can no longer work.
Additionally, there are countless websites that tell of men's experiences and emotional struggles at having had an important part of their body permanently removed for no good reason, long before they had any knowledge or say in it.
Personally, I believe that medically-unnecessary circumcision is only considered in any way acceptable or benign as it is usually done long before the person whose body it is would be in a position to benefit as a sexually-mature adult from his normally-functioning intact body and thus can never fully appreciate what he has lost.
Of course, if a grown man with mental capacity should wish to be circumcised for any reason, even though there is no medical need for it, I would have no problem with his decision to do so. I can't for the life of me understand why people have tattoos and bizarre body piercings and modifications, but as long as they are adults and not vulnerable, it's totally their choice.