I fielded a question from MFTTW on whether First Cousin Marriage was legal in Singapore.
Under the Women's Charter (which covers the marriage of a male non-Muslim and a female non-Muslim),
"A marriage solemnized in Singapore or elsewhere between a man and any of the persons mentioned in the first column of the First Schedule, or between a woman and any of the persons mentioned in the second column of that Schedule, shall be void"
(Section 10[1]).
First Column (people men cannot marry):
Mother.
Daughter.
Father’s mother.
Mother’s mother.
Son’s daughter.
Daughter’s daughter.
Sister.
Wife’s mother.
Wife’s daughter.
Father’s wife.
Son’s wife.
Father’s father’s wife.
Mother’s father’s wife.
Wife’s father’s mother.
Wife’s mother’s mother.
Wife’s son’s daughter.
Wife’s daughter’s daughter.
Son’s son’s wife.
Daughter’s son’s wife.
Father’s sister.
Mother’s sister.
Brother’s daughter.
Sister’s daughter.
Second Column (people women cannot marry):
Father.
Son.
Father’s father.
Mother’s father.
Son’s son.
Daughter’s son.
Brother.
Husband’s father.
Husband’s son.
Mother’s husband.
Daughter’s husband.
Father’s mother’s husband.
Mother’s mother’s husband.
Husband’s father’s father.
Husband’s mother’s father.
Husband’s son’s son.
Husband’s daughter’s son.
Son’s daughter’s husband.
Daughter’s daughter’s husband.
Father’s brother.
Mother’s brother.
Brother’s son.
Sister’s son.
In other words, you can marry your First Cousin in Singapore.