Introduction In some cross sectional studies exposure to PCBs is associated with reduced sperm quality; however, only one small study has investigated prenatal exposure. Methods In a sample of 195 adult men whose mothers were enrolled in Child Health and Development studies in the 1960s, we measured 15 PCB congeners in maternal early postpartum serum in relation to sperm concentration, motility, and morphology in men ages 39 to 47. Linear regression was used to estimate the associations between maternal serum PCB levels and semen parameters, adjusting for potential confounders. Results Higher levels of PCB105 in maternal serum predicted increased sperm concentration in adult sons (estimated adjusted b = 1.9; 95% Confidence Interval (CI) (0.3-3.4)). Higher maternal serum PCB74 predicted increased sperm motility (estimated adjusted b = 24.9; 95% CI (1.9, 48.0)). In contrast, higher maternal serum PCB183 predicted decreased motility (estimated adjusted b= -41.04. 95% CI (-74.7, -7.4)) and higher maternal serum PCB66 and PCB156 predicted decreased percent normal sperm morphology (estimated adjusted b=-4.1; 95% CI (-8.0, -0.3) and estimated adjusted b=-7.1; 95% CI (-13.8, -0.5), respectively Conclusion Maternal perinatal serum levels of five specific PCB congeners predicted measures of semen quality in adult sons. Interestingly, maternal perinatal serum levels of three of these PCBs (105, 183 and 156) also predicted time to pregnancy in adult daughters in the Child Health and Development Studies in a prior report. Findings suggest that perinatal exposure to these three PCBs may result in lasting endocrine disruption in both sexes.