Decline in Human Fertility Rates with Male Age: A Consequence of a Decrease in Male Fecundity with Aging?

Abstract

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. Results: From a demographic point of view, male fertility started to decline at 35–39 years of age. This decline is constant and follows an exponential pattern (slope –0.11 to –0.12). The trend persisted when the data were adjusted for every 1,000 men in the age group, as well as when only women under the age of 30 were considered. Male fertility showed a 21–23% annual decrease starting at the age of 39. Conclusion: An exponential decrease in human fertility which is independent of the woman’s age was observed with male aging. This decay is probably due to a downfall in male fecundity, closely related to a decline in sperm quality. However, social or behavioral causes for this trend cannot be excluded.

A qualitative study of Ottawa university students’ awareness, knowledge and perceptions of infertility, infertility risk factors and assisted reproductive technologies (ART)

“…Although some laboratory studies [44,45] report an association of advanced paternal age and reduced semen quality, other groups found no age effect [46-48]. Similarly, clinical studies both confirm [49,50] and refute [51,52] associations between advanced paternal age and reduced live birth rates. As it seems likely that there is some association between advanced paternal age, infertility and adverse fetal outcomes [53], promotion of fertility preservation should address this risk issue.…”

Lifestyle factors and reproductive health: taking control of your fertility

“…The authors also noted that the older population tended to consume more alcohol, have intercourse less often, had longer contraceptive usage, and smoked less cigarettes which could have been confounding factors. Another study found that there are also exponentially fewer infants born to fathers ≥35 to 39 years of age and older compared to younger age groups even when controlling for female age (n = 122,061) [10]. …”

“…The chances of becoming pregnant and being able to maintain a pregnancy are also affected. Matorras et al reported that in a population of women, the number of infants born begins to exponentially decrease after the age bracket of 35–39 (n = 89,287) [10]. The odds of becoming pregnant and maintaining a pregnancy are believed to be connected to numerous factors, including euploidy.…”

Global Contraceptive Failure Rates: Who Is Most at Risk?

“…One, women's biologic fecundity, or the probability of conception per coital act, decreases with increasing age (Menken, Trussell, and Larsen ), as does their male partner's (Kuhnert ; Matorras et al. ). Two, coital frequency also decreases with age (Westoff ).…”