Virility (from the Latin virilitas, manhood or virility, derived from Latin vir, man) refers to any of a wide range of masculinity characteristics viewed positively. Virile means "marked by strength or force". Oxford English Dictionary Virility is commonly associated with vigour, health, sturdiness, and , 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". Oxford English Dictionary
Historically, masculine attributes such as beard growth have been seen as signs of virility and leadership (for example in ancient Egypt and Greece).
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:
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 |
Research shows increased risks for health problems for children of older fathers. A large-scale 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 an Autism, controlling for year of birth, socioeconomic status, and maternal age. Increased paternal age has also been correlated to schizophrenia in numerous studies.
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.
The American Fertility Society recommends an age limit for sperm donors of 50 years or less, and many in the United Kingdom will not accept donations from men over 40 or 45 years of age." Age Limit of Sperm Donors in the United Kingdom", PDF file
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