Citizenship by descent
A person born outside Singapore on or after 15 May 2004, with at least one parent who is a Singaporean citizen, is a Singaporean citizen by descent. If the parent from whom the child derives citizenship is a Singaporean citizen by descent, the parent must have been resident in Singapore for a total of at least four years before the child's birth or a total of at least one year out of the five years immediately preceding the child's birth.
A person born outside Singapore before 15 May 2004 will be a Singaporean citizen by descent only if his or her father was a Singaporean citizen by birth or by registration at the time of birth.
In all cases, children of Singaporean citizens born overseas will be granted Singaporean citizenship by descent only if they do not acquire citizenship of the country of their birth.
Source: Singaporean nationality law - Wikipedia, the free encyclopedia