why yes I am
if you immunise your son he is more likely to have it when it's dangerous
as shown by the student mumps epidemics of recent years
initally claimed to be because they were too young to have had the mmr ..then claimed to be because they were too young to have had two doses.. now accepted as significant vaccine failure
Aseptic meningitis is common, rarely fatal condition usually caused by certain viruses. It is an illness characterized by serious inflammation of the linings of the brain (ie, meninges), usually with an accompanying mononuclear pleocytosis. Clinical symptomatology is varied and includes predominantly headache and fever. The illness is usually mild and runs its course without treatment.
Fifteen per cent of patients with mumps have an aseptic meningitis. Encephalitis is rare occurring in less than 260 out of 100,000 cases.
Sensorineural deafness occurs in 4 per cent of mumps patients and has also been reported following MMR vaccination. A seven year old girl developed total deafness in the left ear 11 days after an MMR injection without recovery and a three year old girl who received MMR at 15 months developed moderate to severe unremitting sensorineural deafness.
Principles of Neurologic Infectious Diseases, 2005
It means that adolescent girls and women should be vaccinated against rubella, not infants.