Minor Children are allowed to keep dual citizenship till the age of 21 more or less. After they they have to take an oath of allegience and renounce they other citizenship if they want to retain their Singaporean one. The son, once naturalized will be required by law to do National Service and even leaving the country will not remove that obligation unless it is done prior to his 11/13th birthday. There are a number of threads dealing with this in the "Strickly Speaking" Subforum in the General Forum for additional informations.
SOME PEOPLE TRY TO TURN BACK THEIR ODOMETERS. NOT ME. I WANT PEOPLE TO KNOW WHY I LOOK THIS WAY. I'VE TRAVELED A LONG WAY, AND SOME OF THE ROADS WEREN'T PAVED. ~ Will Rogers