出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2016/02/27 02:28:25」(JST)
Look up virility in Wiktionary, the free dictionary. |
Virility (from the Latin virilitas, manhood or virility, derived from Latin vir, man) refers to any of a wide range of masculine characteristics viewed positively. It is applicable to women and not to negative characteristics. The Oxford English Dictionary (OED1) says virile is "marked by strength or force". Virility is commonly associated with vigour, health, sturdiness, and constitution, especially in the fathering of children. In this last sense, virility is to men as fertility is to women. OED1 also notes that virile has become obsolete in referring to a "nubile" young woman, or "a maid that is Marriageable or ripe for a Husband, or Virill".[2]
Historically, masculine attributes such as beard growth have been seen as signs of virility and leadership (for example in ancient Egypt and Greece).[1]
Evidence shows that increased male age is associated with a decline in semen volume, sperm motility, and sperm morphology.[3] In studies that controlled for female age, comparisons between men under 30 and men over 50 found relative decreases in pregnancy rates between 23% and 38%.[3]
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 the seminiferous tubules in the testes contain mature sperm;
Research shows increased risks for health problems for children of older fathers. A large-scale Israeli study found that the children of men 40 or older were 5.75 times more likely than children of men under 30 to have an autism spectrum disorder, controlling for year of birth, socioeconomic status, and maternal age.[5] Increased paternal age has also been correlated to schizophrenia in numerous studies.[6][7][8]
Australian researchers have found evidence to suggest overweight 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.[9]
The American Fertility Society recommends an age limit for sperm donors of 50 years or less,[10] and many fertility clinics in the United Kingdom will not accept donations from men over 40 or 45 years of age.[11] In part because of this fact, more women are now using a take-home baby rate calculator to estimate their chances of success following invitro fertilization.[12]
The New Virility is an article written by Barbara Marshall, discussing the medicalization on erectile dysfunction to prolong male virility. The clinical and market success of Viagra was pivotal in providing the necessary condition for a healthy life and the erectile capacity for virility. Marshall argues that the concept of virility is now concerned with maintenance and enhancement of sexual desire and performance. Besides that, sexual activity is portrayed as a necessary condition for a healthy life and the erectile capacity defines male virility during the whole life span of men. Viagra has changed the approach of erectile dysfunction in the American society, promoting the idea of constant vigilance and the consumption of pills to guarantee erectile health, the symbol of masculinity and physical and emotional health. Marshall concludes that these drugs may help with the "mechanics" but not the true desire a man feels during an erection.[13]
Viagra, Male Aging and Sexual Function Barbara L. Marshall explains that perception virility has changed a great deal since the 20th century. In the early 1900s, decline of sexual stimulation was seen as the natural course of life. It was not until the mid to late 20th century when erectile dysfunction was seen as a physiological disorder. Scientific analysis showed that there is room for medicinal stimulation to induce erections. Now in the 21st century with the introduction of Viagra, erectile dysfunction is seen as a disorder from which many men suffer. This differs from being accepting of the natural decline of sexual stimulation, which was the perception decades ago.
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