The male biological clock is ticking: a review of the literature

Abstract

The term biological clock is usually used by physicians and psychologists to refer to the declining fertility, increasing risk of fetal birth defects and alterations to hormone levels experienced by women as they age. Female fecundity declines slowly after the age of 30 years and more rapidly after 40 and is considered the main limiting factor in treating infertility. However, there are several scientific reports, chapters in books and review articles suggesting that men may also have a biological clock. The aim of our study was to conduct a review of the literature, based on the Medical Literature Analysis and Retrieval System Online (Medline), to evaluate the male biological clock. After adjustments for other factors, the data demonstrate that the likelihood that a fertile couple will take more than 12 months to conceive nearly doubles from 8% when the man is < 25 years old to 15% when he is > 35 years old. Thus, paternal age is a further factor to be taken into account when deciding on the prognosis for infertile couples. Also, increasing male age is associated with a significant decline in fertility (five times longer to achieve pregnancy at the age of 45 years). Patients and their physicians therefore need to understand the effects of the male biological clock on sexual and reproductive health, in that it leads to erectile dysfunction and male infertility, as well as its potential implications for important medical conditions such as diabetes and cardiovascular diseases.

Are Caucasian–European men delaying fatherhood? Results of a 7 year observational study of infertile couples with male factor infertility

“…, 2008). Also, data demonstrated that increasing male age is associated with a significant decline in fertility (five times longer to achieve pregnancy at 45 year of age) (Pasqualotto et al. , 2008), thus supporting the concept that paternal age is an additional factor to take into account when deciding on the prognosis for infertile couples.…”

“…The authors concluded that such a delay may have a large impact on the proportion of involuntarily infertile couples likely to resort to assisted reproductive techniques (Leridon & Slama, 2008). Similarly, a systematic review of the literature in 2008 showed that, after adjustments for other factors, the likelihood that a fertile couple will take >12 months to conceive nearly doubles from 8% when the man is <25 year of age to 15% when he is >35 year of age (Pasqualotto et al. , 2008).…”

Risk Factors and Causes of Male Infertility-A Review

“…Hypogonadism is not defined by any specific level of serum androgens because the testosterone level that causes dysfunction varies widely among individuals [10]. The symptoms associated with symptomatic hypogonadism in aging males include decreased libido, decreased muscle mass, decreased bone mineral density, increased fat mass, central obesity, insulin resistance, emotional irritability, dysphoria and erectile dysfunction [11]. The risk of becoming infertile doubled in men who are over 35 years old compared with men who are under 25 years old, and five times longer to conceive at the age of 45 years [11].…”

“…The symptoms associated with symptomatic hypogonadism in aging males include decreased libido, decreased muscle mass, decreased bone mineral density, increased fat mass, central obesity, insulin resistance, emotional irritability, dysphoria and erectile dysfunction [11]. The risk of becoming infertile doubled in men who are over 35 years old compared with men who are under 25 years old, and five times longer to conceive at the age of 45 years [11]. In a study on a convenient sample of fifty five healthy men ranging in age from 52 to 79 years old compared with a control group of men less than 52 years old found that older men had lower semen volume, with abnormal sperm morphology and reduced vitality [12].…”

Impact of age on male fertility

“…The percentage of couples failing to conceive within 12 cycles increased to an estimated 18-28% between male ages 35 and 40 years. However, male fertility is basically maintained until very late in life, and has been observed to men in their 90s [8].…”