Since you're seeking birth certificates for 1926-1932, you only have two options as these cannot be viewed at the NJ State Archives. Their microfilm records cover the period of 1848-1923.
1) Contact the Health Dept of the municipality where the children were born to conduct the search.
2) Write to the NJ Dept of Health ( http://www.state.nj.us/health/vital/
). Fee is $25.
According to the NJ Dept of Health, Genealogical Records (family history research) are:
Birth, death and marriage records for people who are deceased
* the birth occurred more than 80 years ago
* the marriage occurred more than 50 years ago
* the death occurred more than 40 years ago