The person in question is your son. Think about it this way: Who is "your father's son"? It's you, because you have no brothers or sisters. So, you just replace "your father's son" with "you", and the riddle now reads: "...that man's father is you." Simple.
There is only 3 people. The son, father & grandfather, thus having 2 fathers and 2 sons.
He is your cousin
Either your son or your nephew is the man.Your father's son is either you or your brother (including half-brother).If your father's son is you, then the original man is your son, (you are his father).If your father's son is your brother, then the original man is your nephew, (your brother is his father).Obviously if you have no brothers, than it must be your son.
It is tradition for someone to dance with their father at their Quinceanera. However, if a person has two fathers, you can dance with your father and step-father if you choose.
his brother
My son. "My fathers son" is myself, if I don't have brothers and sisters.Therefore, "A certain man's father is my father's son" simplifies to "A certain man's father is myself".
you/me
his son
The person in question is your son. Think about it this way: Who is "your father's son"? It's you, because you have no brothers or sisters. So, you just replace "your father's son" with "you", and the riddle now reads: "...that man's father is you." Simple.
That means that the man in the photo is his son. "My father's son" is himself (since he has no brothers and sisters); since he is the father of "that man", it follows that "that man" is his son.
His son.
The father's son is the uncle of the son of the father's daughter.
He is your grandson. If his father is your son, he is your grandson.
You
your grandfather is the relative which is described - a) (If I am a female) your grandfather is my father's son, therefore I am your grandaunt (your grandfather is my brother) - b) (If I am a male) your grandfather is my father's son, therefore I am your granduncle (your grandfather is my brother) - c) (but if I am a sole son/daughter) I am your grandfather/grandmother
jesus