@2tfx,
In most cases, the immunization side effects are miniminal and/or so small a percentage it is definately worth it. In other words, the chances of your child were to get some of these diseases/illnesses and how severe the results of such illnesses are much greater than the small chance of a side effect.
Most of these parents are ill (pun intended) informed. Many claim oh no autism where there is no proof there is a relationship -- often times parents panic and do not get all the facts and as a result, although well intentioned, do what is worse for their child.
One thing, I would suggest though - is ask the doctor how long the vaccination has been around for -- sometimes "new" vaccinations are suggested...I would not want my child to be guinea pig either. However the majority of these vaccinations have been in existence for lots of years and therefore side effects are known.