== Family tree and relation to biographer Edgar Bonjour == 

 According to this, the historian Edgar Bonjour ( ) was the son-in-law of Kocher: "A monograph on Kocher’s life was written by the well known Swiss historian and son-in-law Edgar Bonjour [1]".  

 While Bonjour (1898 - 1991) married Dora Kocher (1914-2004), see also , Kocher did not have any daughters and the birth date of 1914 makes it more likely that Dora was a grandchild of Theodor Kocher. From this document "Kocher, Dora und Gertrud an ihre Mutter Kocher, Berta (1880-1929)" it seems that Doras mother was Berta.  

 According to  the most likely family constelation was  

  Theodor Kocher (1841-1917) ∞ Maria Witschi (1841 - 1921) 
  | 
  | Arthur Otto (1876-19?)  [salesman], prob. died between 1925 and 1930 
  | 
  | (Johann) Albert Kocher (1872-1941)  [doctor and lecturer at the university]  
  | 
  | (Albert) Theodor Kocher (1870-1950)  [doctor] ∞ Berta Lauterburg (1880-1929)  
      | 
      |  Gertrud Kocher (1909-?) / Kocher, Gertrud Agnes Friederike (1909-195?) 
      | 
      |  Dora Kocher (1914-2004) ∞ Edgar Bonjour (1898 - 1991) 

 while the Nobel biography describes Johann Albert (1872-1941)  as "oldest" son who became his fathers assistant  he is also the one that is listed as lecturer at the university and thus it is likely that he was the one helping his father but was not the oldest son.