question: Why do men have a refactory period?
comment: The human male penis has a big ridge on it at the glans (the head). The reason this is there is that it creates a suction effect for scooping out semen from a rival male. If there's semen already in there when you're having sex, you'll remove it. You have a refractory period to keep yourself from removing your own semen.
passages: When menarche has failed to occur for more than 3 years after thelarche, or beyond 16 years of age, the delay is referred to as primary amenorrhea.
  
  Section::::Physiology.:Timing.
  
  Section::::Physiology.:Timing.:Chronic illness.
   Since September 2016, Clancy has hosted the Period Podcast, where she discusses issues regarding the science of menstrual cycles. This theme is connected to her early research.
  
  Section::::Fertility research.
   There are two types of amenorrhea. A woman who has been having her period and then stops menstruating for ninety days or more is said to have secondary amenorrhea. In the case of RED-S, the majority of secondary amenorrhea cases are attributed to Functional Hypothalamic Amenorrhea (FHA), an adaptive mechanism to preserve energy for survival and vital processes rather than reproduction when energy balance is low. Primary amenorrhea is characterized by delayed menarche (the onset of menses during puberty). Delayed menarche may be associated with delay of the development of secondary sexual characteristics.
  
  Section::::Signs and symptoms.:Osteoporosis.
   Section::::Fertility biology.:Female fertility.
  
  The average age of menarche in the United States is about 12.5 years. In postmenarchal girls, about 80% of the cycles are anovulatory (ovulation does not actually take place) in the first year after menarche, 50% in the third and 10% in the sixth year.
   Section::::Theories.
  
  During the psychological refractory period, a network of brain regions in both the back and front of the brain are activated. These areas are notable for processing visual information as well as cognitive and motor information respectively. This PRP effect is most likely to be evident when an individual is stressed or is experiencing exhaustion. The PRP is likely caused by a combination of two approaches; the bottleneck approach and the capacity approach. These concepts vary in specific mechanisms, however, they both propose an overall limit to the amount of mental activity in which we can engage in.
   The cessation of menstrual cycles at the end of a woman's reproductive period is termed menopause. The average age of menopause in women is 52 years, with anywhere between 45 and 55 being common. Menopause before age 45 is considered "premature" in industrialised countries. Like the age of menarche, the age of menopause is largely a result of cultural and biological factors; however, illnesses, certain surgeries, or medical treatments may cause menopause to occur earlier than it might have otherwise.
   A woman's fertility peaks in the early and mid-20s, after which it starts to decline slowly. While many sources suggest a more dramatic drop at around 35, this is unclear since studies are still cited from the nineteenth century and earlier. One 2004 study of European women found fertility of the 27–34 and the 35–39 groups had only a four-percent difference. At age 45, a woman starting to try to conceive will have no live birth in 50–80 percent of cases. Menopause, or the cessation of menstrual periods, generally occurs in the 40s and 50s and marks the cessation of fertility, although age-related infertility can occur before then. The relationship between age and female fertility is sometimes referred to as a woman's "biological clock."
   A period-like flow during postmenopause, even spotting, may be a sign of endometrial cancer.
  
  Section::::Management.
  
  Perimenopause is a natural stage of life. It is not a disease or a disorder. Therefore, it does not automatically require any kind of medical treatment. However, in those cases where the physical, mental, and emotional effects of perimenopause are strong enough that they significantly disrupt the life of the woman experiencing them, palliative medical therapy may sometimes be appropriate.
  
  Section::::Management.:Hormone replacement therapy.
   The word "menopause" was coined specifically for human females, where the end of fertility is traditionally indicated by the permanent stopping of monthly menstruations. However, menopause exists in some other animals, many of which do not have monthly menstruation; in this case, the term means a natural end to fertility that occurs before the end of the natural lifespan.
  
  Section::::Evolutionary rationale.
  
  Various theories have been suggested that attempt to suggest evolutionary benefits to the human species stemming from the cessation of women's reproductive capability before the end of their natural lifespan. Explanations can be categorized as adaptive and non-adaptive:
   Menopause is often said to have occurred when a woman has had no vaginal bleeding for over a year since her last menstrual cycle. There are a number of symptoms connected to menopause, most of which can affect the quality of life of a woman involved in this stage of her life. One way to reduce the severity of the symptoms is to exercise and keep a healthy level of fitness. Prior to and during menopause, as the female body changes, there can be physical, physiological or internal changes to the body. These changes can be reduced or even prevented with regular exercise. These changes include:
   Section::::Results.:Aging.
   The menopausal transition, and postmenopause itself, is a natural change, not usually a disease state or a disorder. The main cause of this transition is the natural depletion and aging of the finite amount of oocytes (ovarian reserve). This process is sometimes accelerated by other conditions and is known to occur earlier after a wide range of gynecologic procedures such as hysterectomy (with and without ovariectomy), endometrial ablation and uterine artery embolisation. The depletion of the ovarian reserve causes an increase in circulating follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels because there are fewer oocytes and follicles responding to these hormones and producing estrogen.
   As estrus increases the likelihood of sexually receptive behaviour in females, such that overall reproductive success is more likely, it may be the case that a prolonged estrus cycle is adaptive in the sense of allowing for a longer period of sexual receptivity for successful copulation and reproduction.
   Pregnancy over age 50 has, over recent years, become possible for more women, and more easily achieved for many, due to recent advances in assisted reproductive technology, in particular egg donation. Typically, a woman's fecundity ends with menopause, which, by definition, is 12 consecutive months without having had any menstrual flow at all. During perimenopause, the menstrual cycle and the periods become irregular and eventually stop altogether, but even when periods are still regular, the egg quality of women in their forties is lower than in younger women, making the likelihood of conceiving a healthy baby also reduced, particularly after age 42. It is important to note that the female biological clock can vary greatly from woman to woman. A woman's individual level of fertility can be tested through a variety of methods.
   Section::::Periods for Pence.
  
  The residents of Indiana responded in a campaign that became known as "Periods for Pence". A Facebook page was created anonymously on March 28 urging women from all over the state to send in emails, tweets, and phone calls to the governor's office reporting the progression of their menstrual flow, cramps, birth control, tampon discomfort, bloating, and even menopausal advancements.
   Levinson researched both men and women, and found that they typically go through the same cycles, though he suggested that women's cycles were more closely tied to the domestic sphere, or their family life. Due to the use of biased research methods however, the extent to which his results can be generalized remains controversial. Although not widely accepted, his theories entail many implications for both behavioral and cultural psychology.
  
  Section::::Stages of adult development.
   Menarche
  
  Menarche ( ; Greek: "mēn" "month" + "arkhē" "beginning") is the first menstrual cycle, or first menstrual bleeding, in female humans. From both social and medical perspectives, it is often considered the central event of female puberty, as it signals the possibility of fertility.
   Premenopause is a term used to mean the years leading up to the last period, when the levels of reproductive hormones are becoming more variable and lower, and the effects of hormone withdrawal are present. Premenopause starts some time before the monthly cycles become noticeably irregular in timing.
  
  Section::::Diagnosis.:Perimenopause.
   Age and female fertility
  
  Female fertility is affected by age. Age is thus a major fertility factor for women. Menarche, the first menstrual period, usually occurs around 12–13, although it may happen earlier or later, depending on each girl. After puberty, female fertility increases and then decreases, with advanced maternal age causing an increased risk of female infertility. 
   Section::::Causes.:Menopause.
  
  The female sexual response system is complex and even today, not fully understood. The most prevalent of female sexual dysfunctions that have been linked to menopause include lack of desire and libido; these are predominantly associated with hormonal physiology. Specifically, it is the decline in serum estrogens that causes these changes in sexual functioning. Androgen depletion may also play a role, but currently this is less clear. The hormonal changes that take place during the menopausal transition have been suggested to affect women's sexual response through several mechanisms, some more conclusive than others.
  
  Section::::Causes.:Aging in women.
   Periods for Politicians
  
  Periods for Politicians (originally Periods for Pence) is a campaign launched by the women of Indiana in response to a controversial abortion bill passed by Republican Mike Pence, the fiftieth governor of Indiana, in March 2016. The campaign encourages women to send emails, tweets and phone calls to the governor's office reporting the progression of their menstrual cycles. The group's Facebook page was created March 28 of 2016.
  
  Section::::Background.
   BULLET::::- Fluctuations of hormone levels can result in changes of adequacy of blood supply to parts of the endometrium.
  
  BULLET::::- Death of some of the endometrial tissue from these hormone or blood supply fluctuations leads to "deciduation", a sloughing of part of the lining with some blood flow from the vagina.
  
  No specific hormonal signal for menarche is known; menarche as a discrete event is thought to be the relatively chance result of the gradual thickening of the endometrium induced by rising but fluctuating pubertal estrogen.
   Section::::Productive period.
   Gerald concluded his 2002 review, writing: "This brief review challenges the dogma that male mammals are constantly reproductively active following sexual maturity at puberty. Males of many, and perhaps the majority of, long-lived species, express periodic changes in testicular activity and behaviour during their normal life cycle. In the most extreme examples, as illustrated by the Soay ram, males continually cycle between the sexually active/fertile state and the sexually inactive/infertile state, often on an annual or long-term basis. In individuals, testicular activity may vary with changes in social status, nutrition, health, age and other factors. This also applies to man." 
   Section::::Factors and theories.
  
  While the refractory period varies widely among individuals, ranging from minutes to days, most men cannot achieve or maintain an erection during this time, and many perceive a psychological feeling of satisfaction and are temporarily uninterested in further sexual activity; the penis may be hypersensitive and further sexual stimulation may feel painful during this time frame.
  