Many studies suggest a strong familial component to fibromyalgia (FM). However, these studies have nearly all been confined to individuals with "primary" FM, i.e. FM without any other accompanying disorder. The current 2011-16 criteria for diagnosing FM construct a score using a combination of the number of painful body sites and the severity of somatic symptoms (FM-score). We estimated the genetic heritability of FM-score across sex and age groups to identify subgroups of individuals with greater heritability, which may help in the design of future genetic studies.