Abstract Study question Does paternal occupational exposures to reprotoxic chemical and physical hazards constitute risk factors to cryptorchidism and hypospadias in the offspring? Summary answer Paternal occupational reprotoxic exposures, determined through a job exposure matrix, and paternal rural lifestyle are associated with cryptorchidism, hypospadias, and other genital congenital malformations. What is known already Cryptorchidism and hypospadias are the most common congenital malformations of the male urogenital organs. Over the past century, these congenital malformations, which are associated with testicular cancer and impaired semen quality, have been included into a common disease spectrum known as the testicular dysgenesis syndrome. The association between urogenital congenital malformations and fetal exposure to many factors has been suggested, in particular to genetic and epigenetic factors and environmental factors. There is growing scientific evidence that both maternal and paternal exposure at the time of fertilization play a role after fertilization. Study design, size, duration This is a case-control study with standardized data collection of a 220 father-child cohort recruited from the consultants of our genetic counseling service at the medical university of Sfax (Tunisia), over two years. Participants/materials, setting, methods We compared 110 children diagnosed with congenital malformations to 110 children without any congenital defects. Controls did not differ from the total cohort in confounding variables. Information about paternal jobs held early in pregnancy was collected. Determined via a job exposure matrix, paternal occupational reprotoxic exposures were assessed. Logistic regression analysis was performed to assess the associations between paternal occupational exposures and the congenital testicular dysgenesis syndrome in offspring, including cryptorchidism and hypospadias. Main results and the role of chance 75.54% of children had congenital heart defects and 24.54% of them had genital malformations (n = 27). Paternal occupational exposures to pesticides were associated with the risk of developing birth defects (odds ratio = 17.568 (95% CI), 2.258-136.673). Our results indicate that paternal exposure to pesticides, phthalates, alkylphenolic compounds and other endocrine disruptors was associated with genital and cardiac birth defects. Both cryptorchidism and hypospadias in offspring were associated with paternal rural lifestyle as well as the absence of a maternal job. Limitations, reasons for caution The cohort size in this case-control study may limit the statistical power of the logistical regression to detect associations. Additionally, cases and controls may be selected in a way that does not represent the general population accurately. This can introduce bias and affect the external validity of the study. Wider implications of the findings Including paternal exposures in subsequent investigations of risk factors for cryptorchidism and hypospadias, and further exploring the connection between paternal pesticide exposure and epigenetic alterations, may offer insights into their impact on paternal spermatogenesis, sperm small RNAs, and the potential development of congenital testicular dysgenesis syndrome in future generations. Trial registration number 0400/2022
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