Genetic explanations for anorexia nervosa suggest that genetic factors predispose people to develop this eating disorder. Research has shown that anorexia has a tendency to run in families and concordance rates for identical (MZ) twins are higher than for non-identical (DZ twins). For example, Thornton et al. (2010), found 74% concordance for anorexia nervosa in MZ twins, compared with 28% for DZ twins.