Their daughter?
only if the son is the child of the father. If the father is the son of the child, you might be a redneck.
the daughter
Your half-brother...
someone`s daughter
Your mother's husband is your father. His father-in-law is your mother's father, your grandfather. Your grandfather's son is your mother's brother, and your uncle. Your uncle's daughter is your first cousin.
Mothers are allowed to do that, but you could check adoption records. This type of thing happens frequently in Missouri. A mother moves there from another state, denies the father access, than after six months the child can be adopted by a stepparent, without the father knowing.see link
Ones male child
Son
son
son
The clue is in the question, son/daughter and father.
yep