A perfluoroalkyl substance; embryo-larval exposure induces yolk sac edema and increases mRNA expression of thyroid hormone synthesis genes, including tshβ, in zebrafish at 0.1 and 0.3 mg/L, respectively; decreases serum testosterone and luteinizing hormone levels, testis palmitic acid, linoleic acid, and oleic acid levels, and the number of Leydig cells in rats in late puberty at 10 mg/kg; maternal plasma levels during gestation are positively associated with the development of eczema in female, but not male, infants; liver levels are higher in cancerous human livers compared with non-cancerous human livers; has been found in marine mammals