Decline in human fertility rates with male age: a consequence of a decrease in male fecundity with aging?

Background: The objective of this study is to investigate the influence of male age on human fertility, defined as the birth rate for a given population.

Methods: Data from the Spanish National Statistics Institute (INE) for the year 2004 from a total of 454,753 newborn infants and sorted by male and female age groups were evaluated. In order to correct the influence of female age-related fertility, a different analysis was performed considering only women under 30 years of age.