Virility (from the Latinvirilitas, manhood or virility, derived from Latinvir, man) refers to any of a wide range ofmasculine characteristics viewed positively. Virile means "marked by strength or force".[2] Virility is commonly associated with vigour,health, sturdiness, andconstitution, especially in the fathering of children. In this last sense, virility is to men as fertility is to women.Virile has become obsolete in referring to a "nubile" young woman, or "a maid that is Marriageable or ripe for a Husband, or Virill".[3]
Historically, masculine attributes such asbeard growth have been seen as signs of virility and leadership (for example inancient Egypt andGreece).[1]
Evidence shows that increased male age is associated with a decline in semen volume,sperm motility, and sperm morphology.[4] In studies that controlled for female age, comparisons between men under 30 and men over 50 found relative decreases inpregnancy rates between 23% and 38%.[4]
Older men have lower semen parameters resulting in lower fertility potential. The effects of aging on semen quality are summarized below based on a study of 1,219 subjects:[5]
| Age group (years) | Number of subjects (n) | Volume (ml) [min–max] | Total Sperm count (million) [min–max] | Motility (grades a + b) (%) [min–max] | Morphology (%) [min–max] |
|---|---|---|---|---|---|
| 21–28 | 57 | 2.9±1.3 [1.0–6.0] | 144.3±138.0 [0.2–414] | 47.5±25.4 [0–88] | 26.1±13.3 [0–49] |
| 29–35 | 450 | 2.7±1.5 [0.2–8.0] | 149.5±173.7 [0.1–1358] | 48.1±30.4 [0–95] | 24.8±15.7 [0–55] |
| 36–42 | 532 | 2.5±1.5 [0.4–10.5] | 120.4±156.7 [0.2–949] | 40.0±27.1 [0–83] | 23.1±15.9 [0–56] |
| 43–49 | 165 | 2.4±1.4 [0.1–8.0] | 112.3±142.7 [0.2–776] | 33.1±25.1 [0–84] | 23.0±16.5 [0–60] |
| 50–60 | 15 | 1.7±1.1 [0.5–4.5] | 61.0±91.1 [0.1–329] | 31.3±23.9 [0–59] | 19.7±14.5 [0–37] |
Sperm count declines with age, with men aged 50–80 years producing sperm at an average rate of 75% compared with men aged 20–50 years. However, an even larger difference is seen in how many of theseminiferous tubules in thetestes contain mature sperm:
Research shows increased risks for health problems for children of older fathers. A large-scaleIsraeli study found that the children of men who were 40 or older were 5.75 times more likely than children of men under 30 to have anautism spectrum disorder, controlling for year of birth, socioeconomic status, and maternal age.[7]Increased paternal age has also been correlated to schizophrenia in numerous studies.[8][9][10]
Researchers have found evidence to suggest overweight and obesity may cause subtle damage to sperm and prevent healthy pregnancy. They say fertilization was 40% less likely to succeed when the father was overweight.[11]
TheAmerican Fertility Society recommends an age limit for sperm donors of 50 years or less,[12] and manyfertility clinics in theUnited Kingdom will not accept donations from men over 40 or 45 years of age.[13]
{{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link)