Background Prenatal exposure to endocrine disruptors, like organohalogen compounds (OHCs), might be responsible for the increased aberrations in human male sexual development (hypospadias, cryptorchidism, testicular cancer and fall in sperm count) observed over the past decades. This development is established during fetal life, and reflected in sex hormone levels, testes volume and penile length post-partum. The present study investigates the correlation between prenatal OHC levels and male sexual development outcomes.Methods AND RESULTSLevels of eight neutral [2,2′-bis-(4-chlorophenyl)-1,1′- dichloroethene (4,4′-DDE), 2,2′,4,4′,5,5′- hexachlorobiphenyl, 2,2′,4,4′-tetrabromodiphenyl ether (BDE)-47,-99,-100,-153,-154 and 1,2,5,6,9,10-hexabromocyclododecane, HBCDD] and four phenolic [(pentachlorophenol (PCP), 4OH-CB-107 (4-hydroxy-2,3,3′, 4′,5-pentachlorobiphenyl),-146 and-187)] OHCs were determined in 55 maternal serum samples taken at 35 weeks of pregnancy. Eight sex development-related hormones [testosterone, free testosterone, sex hormone-binding globulin (SHBG); LH, FSH, estradiol (E2), free E2 (FE2) and inhibin B (InhB)] were determined in their sons at 3 months of age, and testes volume and penile length at 3 and 18 months of age. The following prenatal OHC levels correlated significantly with sex hormone levels: PCP with SHBG and InhB (ρ 0.30 and-0.43, respectively), 4OH-CB-107 with testosterone (ρ 0.31) and BDE-154 with FE2, E2 and InhB (ρ 0.49, 0.54 and 0.34, respectively). BDE-154 levels correlated positively with testes volume at 18 months of age (ρ 0.34). Conclusions Prenatal OHC exposure is correlated with aspects of sexual development outcome in boys up to 18 months of age. © 2012 The Author.