Delayed motherhood increases the probability of sons to be infertile.

PurposeTo ascertain whether advanced maternal age at birth is associated with offspring infertility.MethodsA written questionnaire was completed by infertile couples attending our clinic in the presence of a researcher.ResultsMaternal age at birth (odds ratio 1.236, 95% CI 1.100-1.388) and birth order of all respondents and their respective siblings (odds ratio 0.551, 95% CI 0.351-0.865) were significant predictors of male infertility. The probability of a man being infertile increased as mother's age at birth increased (regression coefficient +/- standard error 0.212 +/- 0.059; P < 0.001), but decreased as birth order increased (regression coefficient +/- standard error -0.596 +/- 0.230; P = 0.010).ConclusionsDelayed motherhood may enhance the probability of sons to be infertile. The probability of a man being infertile would be greater if he comes from a small family than if he comes from a large family.