The RelationshipType enum is used to specify the type of relationship.
RelationshipType
FATHER_RELATIONSHIP
Link new individual to existing individual as father
MOTHER_RELATIONSHIP
Link new individual to existing individual as mother
HUSBAND_RELATIONSHIP
Link new individual to existing individual as husband
WIFE_RELATIONSHIP
Link new individual to existing individual as wife
CHILD_RELATIONSHIP
Link new individual to existing individual as child
SIBLING_RELATIONSHIP
Link new individual to existing individual as sibling