Parental Separation and Semen Quality in Young Men: A Population-Based Cohort Study

Purpose: Parental separation may be a stressful life event with the potential to influence hormonal regulation of offspring reproductive health and thereby affect semen quality in young men. We aimed to study the association between parental separation in pregnancy or in childhood and semen quality in young men and to study whether the timing of parental separation in childhood was important. Patients and Methods: We conducted a follow-up study of 1058 young men born 1998-2000 from the Fetal Programming of Semen Quality (FEPOS) cohort nested within the Danish National Birth Cohort. Data on parental separation were obtained longitudinal by self-report. Parental separation in pregnancy was dichotomized, and parental separation in childhood was both dichotomized and categorized according to the timing of parental separation (from birth, from early childhood (0-5 years), and from late childhood (6-10 years)). Semen volume, concentration, total sperm count, motility, morphology, and testes volume were analysed using multivariable negative binomial regression models. Results: Parental separation in pregnancy was not associated with semen quality. The association between parental separation in childhood and semen quality differed with the timing of parental separation. Parental separation from birth was associated with higher semen volume of 25%, 95% CI (-5; 64); higher total sperm count of 62%, 95% CI (-6; 179); and higher proportion of morpholo-gically normal spermatozoa of 59%, 95% CI (20; 111). Parental separation in early childhood was associated with lower semen volume of -14%, 95% CI (-24; -3); lower concentration of -15%, 95% CI (-28; 1); lower total sperm count of -17%, 95% CI (-32; 2) and lower testes volume of -11%, 95% CI (-18; -3). Conclusion: The timing of parental separation was important, and parental separation from birth was associated with higher semen quality, and parental separation in early childhood was associated with lower semen quality.