I honestly can't say why we did it. Just because everyone does, I guess. Being a first time dad, when my oldest was born, I didn't want him getting made fun of in the locker room or anything, and feeling weird, since we live in the Midwest. We were told it decreases chances of infection, etc. Then when the second was born, we did it because the first child was.
If I had to do it over again, I probably wouldn't have it done. I'm just glad that we don't have to deal with it again.