Who should I marry??

A young man went to his father one day to tell him that he wanted to get married. His father was happy for him. Cheerfully, he asked his son who the girl was, and the young man told him that it was Samantha a girl from the neighborhood.

With a sad face the old man said to his son, "I'm sorry to say this son , but I have to. The girl you want to marry is your sister, but please
don't tell your mother." The young man again brought three more names to his old man, but ended up more frustrated
cause the response was still the same.

So he decided to go to his mother. "Mama I want to get married but all
the girls that I love, dad said they are my sisters and I mustn't tell you."

His mother smiling said to him,"Aagh! Don't worry my son, you can marry
any of those girls.
You're not his son anyway, but please don't tell your father."