Firstly, the lack of female characters in The Hobbit. The only female character mentioned by name is Belladonna Took, Bilbo's mother, and she is a long-dead character. Green states that it is usual for women "to be goddesses, monsters, or other stock foils for more complex male characters" (189) in Lord of the Rings, and this is also true of the female characters in The Hobbit. Bilbo's mother is mentioned only to illustrate his adventurous Took side, and is used as a way of illustrating the staid and solid Baggins (a stereotypical hobbit). The Tooks were known to have adventures, although "they discreetly disappeared, and the family hushed it up" (Tolkien, 13) and this is part of the reason that Bilbo rebels, and is "held by all the hobbits of the neighbourhood to be 'queer'" (Tolkien, 363) after his return to Bag End. Green states that Belladonna's "absence [in the later parts of the book] is a presence" (190), as the act of her motherhood of Bilbo, and the succession of her genes is the very reason for the adventure part of the story. Green also states that some of the characters in The Hobbit are androgynous enough to be written as female, in particular any hosts that fulfil the nurturing role as they offer places of security to those members on the quest. The lack of female characters perhaps suggests a resistance against the shallow female characters repeatedly found in adventure or quest tales; those characters that simply fill the role of lover, or nurturer, or evil queen are eliminated from The Hobbit. However any reference to female characters is shallow and shadow-y, leaving the stage clear for the domination of the male characters. This may have been a calculated decision, especially given that Tolkien was a gifted academic and a renowned philologist, and would realise the implications of the elimination of the female from his novel.
Secondly, the links between Tolkien's own war experiences and how they are reflected in his novels is worth looking at. His works are "by no means allegories of that or any other war, yet the impact of the Great War is evident [in his craft]" (Croft, 4). Tolkien acknowledged his war experiences several times, particularly in regards to the character of Samwise Gamgee (based on 'the English soldier'), and the Dead Marshes and the Morannon are based on the terrain after the Battle of the Somme. Tolkien chose to utilize a form of writing different to "the realistic and ironic form many other [World War One] writers used" (Croft, 6), as he worked his war experiences into a fairy-tale-esque or epic tale formula. One critic discusses Tolkien's apparently deliberate use of abstract words "such as glory, honour, courage, or hallow [and] ... how Tolkien ... could have gone through the Great War, with all its rants and lies, and still come out committed to a 'feudal' literary style ... [and concludes that] his tenacity on this point looks like an act of deliberate defiance of modern history" (Croft, 7). Tolkien doesn't shy away from placing war and the impacts of war at the forefront of his novels, but he doesn't demonize war as many other WWI authors did. Instead he almost harks back to the pre-WWI perspective of war as a necessity, and something that would grant great glory and riches to those who were involved.
Both of these perspectives on Tolkien's work, and here we must consider his work as a whole rather than isolating The Hobbit, are particularly interesting and perhaps have intersecting points. The fact that Tolkien began to work on the world-building of Middle Earth during World War One perhaps indicates the ongoing impact that the war had on later works. The thread of war is significant in each of Tolkien's novels (either on a world affecting scale or on a smaller scale of geographical impact - for example the Mistwood/Lonely Mountain area in The Hobbit), and this can be attributed to Tolkien's personal experience of war. The lack of female characters in The Hobbit could also be attributed to WWI and the way female personnel were liminated from combat zones and protected from the horrors, although this would perhaps be a stretch, but the seeds of a theory of this nature are visible. Overall, despite Tolkien's hate of critical analysis of works based on the life story of the author, personal events in the authors life will affect any work they create, whether this is intentional or accidental.