\[ \begin{array}{c} \textbf{C} \quad (\text{Father}) \\ \downarrow \\ \begin{array}{ccc} \textbf{A} (\text{Male}) & \quad\quad & \textbf{B} (\text{Parent}) \\ & & \downarrow \\ & & \begin{array}{cc} \textbf{D} (\text{Male)} & \quad \textbf{E} (\text{Female)} \end{array} \end{array} \end{array} \] C is the father of A and B.
A (Male) and B (Parent) are siblings.
B has two children: D (Male) and E (Female).
A is the uncle of D.