The film Let the Right One In directed by Tomas Alfredson uses the vampire story to examine the concept of the "other". There are two others in our film but the focus of this study will be on Eli.
Background for Eli: (Spoiler warning) Edit
Eli moves into an apartment in Blackeburg Stockholm with a man named Håken, here she meets a 12 year old boy named Oskar who lives with his mother and who is being bullied at school. Although Oksar finds Eli to be a bit peculiar the two become friends and find solace in one another. Eli however is more peculiar than Oskar could ever imagine, she is a vampire. Håken, who severs as her Reinfeild, gathers blood for her but after he is caught she is forced to hunt for herself. She is overcome with hunger and her hunting is sloppy, getting the attention of some of the locals. Although she is fending for herself her relationship with Oskar grows and he falls in love with her and accepts her being a vampire. 
Eli as the Other: Edit
"Othering" is the categorization of a person or a group of people as not one of us.  Who constitutes the "other" changes between cultures and societies and evolves over time. Most often "others" are those who deviate from social norms and standard notions of beauty. Gender, sex, sexual orientation, class, race, physical and mental disabilities, etc., can all be basis for "othering". Since its origin in Eastern European folklore the vampire has represented the "others". According to Jeffrey Cohen vampires make us question our perceptions and our misinterpretations of the world. "They ask us to reevaluate our cultural assumptions about race, gender, sexuality, our perception of difference, our tolerance towards its expression."  Eli's "othering" stems from her gender. At several points in the film Oskar indicates his desire for a romantic relationship with Eli but she asks him if he would still care about her if she wasn't a girl. On the outside Eli is identifiable as female even though she can be androgynous at times. However, Oskar and the audience learns that Eli is a castrated boy, in a scene where Eli is changing clothes we catch a glimpse of a scar across her pubic area and no indication of female genitalia. People with ambiguous gender have long been seen as monstrosities. Children born with ambiguous genitalia were often forced to have gender reassignment surgery with no regard to which gender they identify as. Adults who don't fit in a gender binary society are excluded and shunned. Although Eli isn't intersex, in that she wasn't born with an ambiguous gender, she represents societal fears of gender ambiguity. Like Oskar we grow to care for Eli and sympathize with her and when we learn about her gender ambiguity we are forced to question our perception.