Objectives Hypospadias is a urogenital birth defect affecting infant boys. Periconceptual parental occupational exposure to endocrine disrupting chemicals (EDCs) with oestrogenic or anti-androgenic properties may adversely affect male genital development in utero. The aim of this study was to investigate the association between both maternal and paternal occupational exposures to EDCs and hypospadias.

Methods This registry-based case–control study considered 1202 cases of hypospadias in children born in Western Australia between 1980 and 2000 and 2583 male controls randomly selected from birth records for whom information regarding parental occupation was available from the Western Australian Maternal and Child Health Research Database. Occupational exposures to seven groups of potential EDCs were independently coded by two researchers according to a validated job–exposure matrix.

Results Multivariable analysis showed a strong association with potential maternal occupational exposure to heavy metals with an over twofold increased risk of hypospadias (OR 2.6; 95% CI 1.3 to 5.2), and women exposed to phthalates were more likely to have an affected son (OR 1.2; 95% CI 0.8 to 1.7). Compared with mild or isolated cases, the risks of moderate–severe hypospadias or multiple defects were increased up to two- and fivefold, respectively, with maternal exposure to most types of EDCs. Paternal occupational exposures to polychlorinated organic (OR 1.3; 95% CI 1.0 to 1.8) and bi-phenolic (OR 1.6; 95% CI 1.0 to 2.6) compounds were also possible risk factors.

Conclusions Our findings provide preliminary evidence of an association between exposure to EDCs with oestrogenic or anti-androgenic properties and increased risk of hypospadias.