I have no friend
The first embarkation on a major and, to some critics, puzzling feature of this novel, its all but exclusive emphasis on male bonding.
If we consider novels that are contemporary with Frankenstein and have been accorded a similar canonical reputation, we might expect a woman novelist to emphasize the richness of female relationships (for instance, the sisters of Austen's Sense and Sensibility or Pride and Prejudice) and a man (the classic example might be Walter Scott in Ivanhoe) to concentrate on the representation of male competition and loyalties.
Perhaps, however, we are overly conditioned by stereotypes. On the one hand, there is the fact that Frankenstein was published anonymously and was taken by at least one critic, Walter Scott himself, to be the work of a male author (see his review in Blackwood's Edinburgh Magazine). From this it could be argued that Mary Shelley might have wished to escape the preoccupation with female experience in contemporary "lady novelists." And on the other hand, from a feminist perspective it could likewise be argued that a women might have a very different take on that male competition and loyalty than a man. Inasmuch as masculine terms might be said to define the boundaries of a woman's existence, Mary Shelley might have thought an exclusionary male experience to be a province to which she had every right to demand access. This would have been particularly the case in 1816, after nearly a quarter century of almost continuous warfare in Europe.