Problem - 4719
$\textbf{Son}$
A father and son suddenly have a car accident. Father dies on the spot but the child is rushed to the hospital. When he arrives in the hospital, the doctor says, "I can not operate on this child, he is my son!" How can this be?$\textbf{Answer}$
The doctor is his mother.
$\textbf{Note}$
This is one of the simplest inter-person relationship related brain teasers. Most problems of this kind, if not all, exploit the fact that relationships are one to many, not one to one. For example, in this problem, the boy is the son of the father, but he can also be the son of someone else, i.e. the mother.