________________________
                                                     |                        
                        _____________________________|
                       |                             |
                       |                             |________________________
                       |                                                      
 _Robert P. KOCH ______|
| (1960 - ....) m 1992 |
|                      |                              ________________________
|                      |                             |                        
|                      |_____________________________|
|                                                    |
|                                                    |________________________
|                                                                             
|
|--Robert David KOCH 
|  (1993 - ....)
|                                                     _Prescott Sheldon BUSH _+
|                                                    | (1895 - 1972) m 1921   
|                       _George Herbert Walker BUSH _|
|                      | (1924 - 2018) m 1945        |
|                      |                             |_Dorothy Wear WALKER ___+
|                      |                               (1901 - 1992) m 1921   
|_Dorothy Walker BUSH _|
  (1959 - ....) m 1992 |
                       |                              _Marvin PIERCE _________+
                       |                             | (1893 - 1969) m 1918   
                       |_Barbara PIERCE _____________|
                         (1925 - 2018) m 1945        |
                                                     |_Pauline ROBINSON ______+
                                                       (1896 - 1949) m 1918