In her comment on my post 'Why I chose hunger', Renee pointed out that I hadn't mentioned genetics in my post. The issue of whether there's a genetic component to eating disorders is one I personally find pretty interesting and am undecided on.
I think it's pretty much an established statistic that people with a first degree relative with an ED are more likely to develop one themselves than people without. However, since family members tend to share the same environment and tend to influence one another, we can't be certain whether EDs run in families as a result of nature or nurture. Studies which compare the prevalence of EDs in genetically identical twins (monozygotic) verses non-identical (dizygotic) twins are a bit more helpful. In my research of my problem, I came across a study by Holland & Kendler which took a whole bunch of anorexics who happened to be twins and checked whether their twin hand an eating disorder too. They found that, where one a twin has anorexia nervosa, there's a 55% chance that her twin also does if her twin is identical, but only a 7% chance if her twin is non-identical. This does seem to suggest there's a genetic component involved. Some researchers even think they're getting closer to identifying a gene that might make carriers more vulnerable to anorexia: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC384957/
My real difficulty with the genetic theory is not really evidence, though, so much as whether its helpful to my recovery. For me personally, focusing on the genetic arguments doesn't motivate me to work on recovery. Instead, it leaves me feeling hopeless - like a victim of my genes. After all, you can't change your genes. So, I prefer to remember that 45% anorexic girls in Holland & Kendler's study, had a genetically identical twins who hadn't followed their sisters along the self-starvation road. How inspiring is that?! Imagine having a twin who looks exactly like you and thinks they're fat and refuses to eat, and yet finding the strength to just soldier on, stay healthy, and ignore the pressure to diet. What that tells me is that we can over-ride the power of any genetic pre-disposition we may or may not have, if we stay strong. That's what I want to do, so that's what I chose to focus on.