It has been argued that the "rib" ( Hebrew   צֵלׇע   ṣēlāʿ , also translated "flank" or "side") in the story of  Adam and Eve  is actually a mistranslation of a  Biblical Hebrew  euphemism for baculum, and that its removal from Adam in the  Book of Genesis  is a  creation story  to explain this absence (as well as the presence of the  perineal raphe  – as a resultant "scar") in humans. [ 52 ]


In  Hoodoo , the folk magic of the  American South , the raccoon baculum is sometimes worn as an amulet for love or luck. [ 53 ]


Oosik  ( Iñupiaq :  usuk  or  uzuk ) is a term used in  Alaska Native cultures  to describe the bacula of  walruses ,  seals ,  sea lions  and  polar bears . Sometimes as long as 60 cm (24 in), fossilized bacula are often polished and used as a handle for knives and other tools. The  oosik  is a polished and sometimes carved baculum of these large northern carnivores.


Oosiks  are also sold as tourist souvenirs. In 2007, a 4.5 ft-long (1.4 m) fossilized penis bone from an extinct species of walrus, believed by the seller to be the largest in existence, was sold for $8,000. [ 54 ]


United States Congressman  for  Alaska ,  Don Young , was known for possessing an 18-inch walrus  oosik , and once brandished it like a sword during a congressional hearing. [ 55 ]


Benign prostatic hyperplasia  ( BPH ), also called  prostate enlargement , is a noncancerous increase in size of the  prostate gland . [ 1 ]  Symptoms may include  frequent urination , trouble starting to urinate, weak stream,  inability to urinate , or  loss of bladder control . [ 1 ]  Complications can include  urinary tract infections ,  bladder stones , and  chronic kidney problems . [ 2 ]


The cause is unclear. [ 1 ]  Risk factors include a family history,  obesity ,  type 2 diabetes , not enough exercise, and  erectile dysfunction . [ 1 ]  Medications like  pseudoephedrine ,  anticholinergics , and  calcium channel blockers  may worsen symptoms. [ 2 ]  The underlying mechanism involves the prostate pressing on the  urethra  and thereby making it difficult to pass urine out of the  bladder . [ 1 ]  Diagnosis is typically based on symptoms and  examination  after ruling out other possible causes. [ 2 ]


Treatment options include lifestyle changes, medications, a number of procedures, and surgery. [ 1 ] [ 2 ]  In those with mild symptoms, weight loss, decreasing  caffeine  intake, and exercise are recommended, although the quality of the evidence for exercise is low. [ 2 ] [ 4 ]  In those with more significant symptoms, medications may include  alpha blockers  such as  terazosin  or  5α-reductase inhibitors  such as  finasteride . [ 1 ]  Surgical removal of part of the prostate may be carried out in those who do not improve with other measures. [ 2 ]  Some  herbal medicines  that have been studied, such as  saw palmetto , have not been shown to help. [ 2 ]  Other herbal medicines somewhat effective at improving urine flow include  beta-sitosterol [ 5 ]  from  Hypoxis rooperi  (African star grass),  pygeum  (extracted from the bark of  Prunus africana ), [ 6 ]  pumpkin seeds ( Cucurbita pepo ), and  stinging nettle  ( Urtica dioica ) root. [ 7 ]


As of 2019 [update] , about 94 million men aged 40 years and older are affected globally. [ 3 ]  BPH typically begins after the age of 40. [ 1 ]  The  prevalence  of clinically diagnosed BPH peaks at 24% in men aged 75–79 years. [ 3 ]  Based on  autopsy  studies, half of males aged 50 and over are affected, and this figure climbs to 80% after the age of 80. [ 3 ]  Although  prostate specific antigen  levels may be elevated in males with BPH, the condition does not increase the risk of  prostate cancer . [ 8 ]


BPH is the most common cause of  lower urinary tract symptoms  (LUTS), which are divided into storage,  voiding , and symptoms which occur after urination. [ 12 ]  Storage symptoms include the need to urinate frequently,  waking at night to urinate ,  urgency  (compelling need to void that cannot be deferred),  involuntary urination , including involuntary urination at night, or  urge incontinence  (urine leak following a strong sudden need to urinate). [ 13 ]  Voiding symptoms include  urinary hesitancy  (a delay between trying to urinate and the flow actually beginning), intermittency (not continuous), [ 14 ]  involuntary interruption of voiding, weak urinary stream, straining to void, a sensation of incomplete emptying, and uncontrollable leaking after the end of urination. [ 15 ] [ 16 ] [ 17 ]  These symptoms may be accompanied by bladder pain or pain while urinating, called  dysuria . [ 18 ]


Bladder outlet obstruction  (BOO) can be caused by BPH. [ 19 ]  Symptoms are abdominal pain, a continuous feeling of a full bladder, frequent urination, acute urinary retention (inability to urinate), pain during urination (dysuria), problems starting urination (urinary hesitancy), slow urine flow, starting and stopping (urinary intermittency), and nocturia. [ 20 ]


BPH can be a progressive disease, especially if left untreated. Incomplete voiding results in residual urine or urinary stasis, which can lead to an increased risk of  urinary tract infection . [ 21 ]


Most experts consider  androgens  ( testosterone  and related  hormones ) to play a permissive role in the development of BPH. This means that androgens must be present for BPH to occur, but do not necessarily directly cause the condition. This is supported by evidence suggesting that  castrated  boys do not develop BPH when they age. In a study of 26  eunuchs  from the palace of the  Qing dynasty  still living in  Beijing  in 1960, the prostate could not be felt in 81% of the studied eunuchs. [ 22 ]  The average time since castration was 54 years (range, 41–65 years). On the other hand, some studies suggest that administering exogenous testosterone is not associated with a significant increase in the risk of BPH symptoms, so the role of testosterone in prostate cancer and BPH is still unclear. Further randomized controlled trials with more participants are needed to quantify any risk of giving exogenous testosterone. [ 23 ]


Dihydrotestosterone  (DHT), a  metabolite  of testosterone, is a critical mediator of prostatic growth. DHT is synthesized in the prostate from circulating testosterone by the action of the  enzyme   5α-reductase , type 2. DHT can act in an  autocrine  fashion on the stromal cells or in  paracrine  fashion by diffusing into nearby  epithelial cells . In both of these cell types, DHT binds to nuclear  androgen receptors  and signals the  transcription  of  growth factors  that are mitogenic to the epithelial and stromal cells. DHT is ten times more potent than testosterone because it dissociates from the androgen receptor more slowly. The importance of DHT in causing  nodular  hyperplasia is supported by clinical observations in which an  inhibitor  of 5α-reductase such as  finasteride  is given to men with this condition. Therapy with a 5α-reductase inhibitor markedly reduces the DHT content of the prostate and, in turn, reduces prostate volume and BPH symptoms. [ 24 ] [ 25 ]


Testosterone promotes prostate cell proliferation, [ 26 ]  but relatively low levels of serum testosterone are found in patients with BPH. [ 27 ] [ 28 ]  One small study has shown that medical castration lowers the serum and prostate hormone levels unevenly, having less effect on testosterone and dihydrotestosterone levels in the prostate. [ 29 ]


Besides testosterone and DHT, other androgens are also known to play a crucial role in BPH development.  C 21  11-oxygenated steroids (pregnanes) have been identified are precursors to 11-oxygenated androgens which are also potent agonists for the androgen receptor. [ 30 ]  Specifically, steroids like  11β-hydroxyprogesterone  and  11-ketoprogesterone  can be converted to  11-ketodihydrotestosterone , an 11-oxo form of DHT with the same potency. These precursors have also been detected in tissue  biopsy  samples from patients with BPH, as well as in their serum levels. [ 31 ] [ 32 ] [ 33 ]  Besides that, androgens biosythnesized via a  backdoor pathway  can contribute to the development of BPH. [ 31 ]


While there is some evidence that estrogen may play a role in the cause of BPH, this effect appears to be mediated mainly through local conversion of androgens to estrogen in the prostate tissue rather than a direct effect of estrogen itself. [ 34 ]  In canine  in vivo  studies castration, which significantly reduced androgen levels but left estrogen levels unchanged, caused significant atrophy of the prostate. [ 35 ]  Studies looking for a correlation between prostatic hyperplasia and serum estrogen levels in humans have generally shown none. [ 28 ] [ 36 ]


In 2008, Gat et al. published evidence that BPH is caused by failure in the spermatic venous drainage system resulting in increased hydrostatic pressure and local testosterone levels elevated more than 100 fold above serum levels. [ 37 ]  If confirmed, this mechanism explains why serum androgen levels do not seem to correlate with BPH and why giving exogenous testosterone would not make much difference.


Studies indicate that dietary patterns may affect development of BPH, but further research is needed to clarify any important relationship. [ 38 ]  Studies from China suggest that greater protein intake may be a factor in development of BPH. Men older than 60 in rural areas had very low rates of clinical BPH, while men living in cities and consuming more animal protein had a higher incidence. [ 39 ] [ 40 ]  On the other hand, a study in Japanese-American men in Hawaii found a strong negative association with alcohol intake, but a weak positive association with beef intake. [ 41 ]  In a large prospective cohort study in the US (the Health Professionals Follow-up Study), investigators reported modest associations between BPH (men with strong symptoms of BPH or surgically confirmed BPH) and total energy and protein, but not fat intake. [ 42 ]  There is also epidemiological evidence linking BPH with  metabolic syndrome  (concurrent  obesity , impaired glucose metabolism and  diabetes ,  high triglyceride levels , high levels of low-density cholesterol, and  hypertension ). [ 43 ]


Benign prostatic hyperplasia is an age-related disease. Misrepair-accumulation aging theory [ 44 ]  suggests that development of benign prostatic hyperplasia is a consequence of  fibrosis  and weakening of the muscular tissue in the prostate. [ 45 ]  The muscular tissue is important in the functionality of the prostate, and provides the force for excreting the fluid produced by prostatic glands. However, repeated contractions and dilations of myofibers will unavoidably cause injuries and broken myofibers. Myofibers have a low potential for regeneration; therefore, collagen fibers need to be used to replace the broken myofibers. Such misrepairs make the muscular tissue weak in functioning, and the fluid secreted by glands cannot be excreted completely. Then, the accumulation of fluid in glands increases the resistance of muscular tissue during the movements of contractions and dilations, and more and more myofibers will be broken and replaced by collagen fibers. [ 46 ]


As men age, the enzymes  aromatase  and  5-alpha reductase  increase in activity. These enzymes are responsible for converting androgen hormones into  estrogen  and  dihydrotestosterone , respectively. This metabolism of androgen hormones leads to a decrease in testosterone but increased levels of DHT and estrogen.


Both the glandular epithelial cells and the stromal cells (including muscular fibers) undergo hyperplasia in BPH. [ 2 ]  Most sources agree that of the two tissues, stromal hyperplasia predominates, but the exact ratio of the two is unclear. [ 47 ] : 694


Anatomically the median and lateral lobes are usually enlarged, due to their highly glandular composition. The anterior lobe has little in the way of glandular tissue and is seldom enlarged. (Carcinoma of the prostate typically occurs in the posterior lobe – hence the ability to discern an irregular outline per rectal examination). The earliest microscopic signs of BPH usually begin between the age of 30 and 50 years old in the PUG, which is posterior to the proximal urethra. [ 47 ] : 694   In BPH, the majority of growth occurs in the transition zone (TZ) of the prostate. [ 47 ] : 694   In addition to these two classic areas, the peripheral zone (PZ) is also involved to a lesser extent. [ 47 ] : 695   Prostatic cancer typically occurs in the PZ. However, BPH nodules, usually from the TZ are often biopsied anyway to rule out cancer in the TZ. [ 47 ] : 695   BPH can be a progressive growth that in rare instances leads to exceptional enlargement. [ 48 ]  In some males, the prostate enlargement exceeds 200 to 500 grams. [ 48 ]  This condition has been defined as giant prostatic hyperplasia (GPH). [ 48 ]


The clinical diagnosis of BPH is based on a history of LUTS (lower urinary tract symptoms), a digital rectal exam, and exclusion of other causes of similar signs and symptoms. The degree of LUTS does not necessarily correspond to the size of the prostate. An enlarged prostate gland on  rectal examination  that is symmetric and smooth supports a diagnosis of BPH. [ 2 ]  However, if the prostate gland feels asymmetrical, firm, or nodular, this raises concern for prostate cancer. [ 2 ]


Validated questionnaires such as the American Urological Association Symptom Index (AUA-SI), the  International Prostate Symptom Score  (I-PSS), and more recently the UWIN score (urgency, weak stream, incomplete emptying, and nocturia) are useful aids to making the diagnosis of BPH and quantifying the severity of symptoms. [ 2 ] [ 49 ] [ 50 ]


Urinalysis  is typically performed when LUTS are present and BPH is suspected to evaluate for signs of a urinary tract infection,  glucose in the urine  (suggestive of diabetes), or  protein in the urine  (suggestive of kidney disease). [ 2 ]  Bloodwork including  kidney function tests  and  prostate specific antigen  (PSA) are often ordered to evaluate for kidney damage and prostate cancer, respectively. [ 2 ]  However, checking blood PSA levels for  prostate cancer screening  is controversial and not necessarily indicated in every evaluation for BPH. [ 2 ]  Benign prostatic hyperplasia and prostate cancer are both capable of increasing blood PSA levels and PSA elevation is unable to differentiate these two conditions well. [ 2 ]  If PSA levels are checked and are high, then further investigation is warranted. Measures including PSA density, free PSA, rectal examination, and transrectal  ultrasonography  may be helpful in determining whether a PSA increase is due to BPH or prostate cancer. [ 2 ]


Uroflowmetry is done to measure the rate of urine flow and total volume of urine voided when the subject is urinating. [ 51 ]


Abdominal ultrasound examination of the prostate and  kidneys  is often performed to rule out  hydronephrosis  and hydroureter. Incidentally, cysts, tumours, and stones may be found on ultrasound.  Post-void residual volume  of more than 100 ml may indicate significant obstruction. [ 52 ]  Prostate size of 30 cc or more indicates enlargement of the prostate. [ 53 ]


Prostatic calcification  can be detected through transrectal ultrasound (TRUS). Calcification is due to solidification of prostatic secretions or calcified  corpora amylacea  ( hyaline  masses on the prostate gland). Calcification is also found in a variety of other conditions such as prostatitis,  chronic pelvic pain syndrome , and prostate cancer. [ 54 ] [ 55 ]  For those with elevated levels of PSA, TRUS guided biopsy is performed to take a sample of the prostate for investigation. [ 56 ]  Although MRI is more accurate than TRUS in determining prostate volume, TRUS is less expensive and almost as accurate as MRI. Therefore, TRUS is still preferred to measure prostate volume. [ 57 ]


The differential diagnosis for LUTS is broad and includes various medical conditions, neurologic disorders, and other diseases of the bladder, urethra, and prostate such as  bladder cancer , urinary tract infection,  urethral stricture ,  urethral calculi (stones) ,  chronic prostatitis , and prostate cancer. [ 2 ]   Neurogenic bladder  can cause urinary retention and cause symptoms similar to those of BPH. This may occur as a result of uncoordinated contraction of the bladder muscle or impairment in the timing of bladder muscle contraction and urethral sphincter relaxation. [ 2 ]  Notable causes of neurogenic bladder include disorders of the  central nervous system  such as  Parkinson's disease ,  multiple sclerosis , and  spinal cord injuries  as well as disorders of the peripheral nervous system such as  diabetes mellitus ,  vitamin B12 deficiency , and  alcohol-induced nerve damage . [ 2 ]  Individuals affected by  heart failure  often experience nighttime awakenings to urinate due to redistribution of fluid accumulated in swollen legs. [ 2 ]


Certain medications can increase urination difficulties by increasing bladder outlet resistance due to increased  smooth muscle  tone at the prostate or bladder neck and contribute to LUTS. [ 2 ]   Alpha-adrenergic agonist  medications, such as  decongestants  with  pseudoephedrine  can increase bladder outlet resistance. [ 2 ]  In contrast,  calcium channel blockers  and  anticholinergic  medications can worsen urinary retention by promoting bladder muscle relaxation. [ 2 ]  Diuretic medications such as  loop diuretics  (e.g.,  furosemide ) or  thiazides  (e.g.,  chlorthalidone ) can cause or worsen urinary frequency and nighttime awakenings to urinate. [ 2 ]


When treating and managing benign prostatic hyperplasia, the aim is to prevent complications related to the disease and improve or relieve symptoms. [ 58 ]  Approaches used include lifestyle modifications, medications, catheterisation and surgery.


Lifestyle alterations to address the symptoms of BPH include physical activity, [ 59 ]  decreasing fluid intake before bedtime, moderating the consumption of alcohol and caffeine-containing products and following a timed voiding schedule.


Patients can also attempt to avoid products and medications with  anticholinergic  properties that may exacerbate urinary retention symptoms of BPH, including  antihistamines ,  decongestants ,  opioids , and  tricyclic antidepressants ; however, changes in medications should be done with input from a medical professional. [ 60 ]


Physical activity has been recommended as a treatment for urinary tract symptoms. A 2019 Cochrane review of six studies involving 652 men assessing the effects of physical activity alone, physical activity as a part of a self-management program, among others.  However, the quality of evidence was very low and therefore it remains uncertain whether physical activity is helpful in men experiencing urinary symptoms caused by benign prostatic hyperplasia. [ 61 ]


Voiding position when urinating may influence urodynamic parameters (urinary flow rate, voiding time, and post-void residual volume). [ 62 ]  A  meta-analysis  found no differences between the standing and sitting positions for healthy males, but that, for elderly males with lower urinary tract symptoms, voiding in the sitting position--  [ 63 ]


This  urodynamic  profile is associated with a lower risk of urologic complications, such as  cystitis  and  bladder stones .


The two main medication classes for BPH management are  alpha blockers  and  5α-reductase inhibitors . [ 64 ]


Selective α 1 -blockers  are the most common choice for initial therapy. [ 65 ] [ 66 ] [ 67 ]  They include  alfuzosin , [ 68 ] [ 69 ]   doxazosin , [ 70 ]   silodosin ,  tamsulosin ,  terazosin , and  naftopidil . [ 58 ]  They have a small to moderate benefit at improving symptoms. [ 71 ] [ 58 ] [ 72 ]  Selective alpha-1 blockers are similar in effectiveness but have slightly different side effect profiles. [ 71 ] [ 58 ] [ 72 ]  Alpha blockers relax smooth muscle in the prostate and the bladder neck, thus decreasing the blockage of urine flow. Common side effects of alpha blockers include  orthostatic hypotension  (a head rush or dizzy spell when standing up or stretching),  ejaculation  changes,  erectile dysfunction , [ 73 ]  headaches, nasal congestion, and weakness. For men with  LUTS  due to an enlarged prostate, the effects of naftopidil, tamsulosin and silodosin on urinary symptoms and quality of life may be similar. [ 58 ]  Naftopidil and tamsulosin may have similar levels of unwanted sexual side effects but fewer unwanted side effects than silodosin. [ 58 ]


Tamsulosin and silodosin are selective α1 receptor blockers that preferentially bind to the α1A receptor in the prostate instead of the α1B receptor in the blood vessels. Less-selective α1 receptor blockers such as terazosin and doxazosin may lower blood pressure. The older, less selective α1-adrenergic blocker prazosin is not a first line choice for either  high blood pressure  or prostatic hyperplasia; it is a choice for patients who present with both problems at the same time. The older, broadly non-selective alpha blocker medications such as  phenoxybenzamine  are not recommended for control of BPH. [ 74 ]  Non-selective alpha blockers such as terazosin and doxazosin may also require slow dose adjustments as they can lower blood pressure and cause  syncope  (fainting) if the response to the medication is too strong.


The 5α-reductase inhibitors  finasteride  and  dutasteride  may also be used in people with BPH. [ 75 ]  These medications inhibit the  5α-reductase  enzyme, which, in turn, inhibits production of  DHT , a hormone responsible for enlarging the prostate. Effects may take longer to appear than alpha blockers, but they persist for many years. [ 76 ]  When used together with alpha blockers, no benefit was reported in short-term trials, but in a longer-term study (3–4 years) there was a greater reduction in BPH progression to acute urinary retention and surgery than with either agent alone, especially in people with more severe symptoms and larger prostates. [ 77 ] [ 78 ] [ 79 ]  Other trials have confirmed reductions in symptoms, within 6 months in one trial, an effect that was maintained after withdrawal of the alpha blocker. [ 78 ] [ 80 ]  Side effects include decreased  libido  and ejaculatory or erectile dysfunction. [ 81 ] [ 82 ]  The 5α-reductase inhibitors are contraindicated in pregnant women because of their  teratogenicity  due to interference with fetal testosterone metabolism, and as a precaution, pregnant women should not handle crushed or broken tablets. [ 83 ]


A 2018 Cochrane review of studies on men over 60 with moderate to severe  lower urinary tract symptoms  analyzed the impacts of  phosphodiesterase inhibitors  (PDE) in comparison to other drugs. [ 90 ]  These drugs may improve urinary symptoms slightly and reduce urinary bother but may also cause more side effects compared to placebo. The evidence in this review found that there is probably no difference between PDE and  alpha blockers , however when used in combination they may provide a greater improvement in symptoms (with more side effects). PDE also likely improves symptoms when used in combination with  5-alpha reductase inhibitors .


Several phosphodiesterase-5 inhibitors are also effective, but may require multiple doses daily to maintain adequate urine flow. [ 91 ] [ 92 ]   Tadalafil , a phosphodiesterase-5 inhibitor, was considered then rejected by NICE in the UK for the treatment of symptoms associated with BPH. [ 93 ]  In 2011, the U.S. Food and Drug Administration approved tadalafil to treat the signs and symptoms of benign prostatic hyperplasia, and for the treatment of BPH and erectile dysfunction (ED), when the conditions occur simultaneously. [ 94 ]


Antimuscarinics  such as  tolterodine  may also be used, especially in combination with alpha blockers. [ 95 ]  They act by decreasing  acetylcholine  effects on the smooth muscle of the  bladder , thus helping control symptoms of an  overactive bladder . [ 96 ]


Intermittent  urinary catheterization  is used to relieve the bladder in people with  urinary retention . Self-catheterization is an option in BPH when it is difficult or impossible to completely empty the bladder. [ 97 ]   Urinary tract infection  is the most common complication of intermittent catheterization. [ 98 ]  Several techniques and types of catheter are available, including sterile (single-use) and clean (multiple use) catheters, but, based on current information, none is superior to others in reducing the incidence of urinary tract infection. [ 99 ]


If medical treatment is not effective, surgery may be performed. Surgical techniques used include the following:


Other less invasive surgical approaches (requiring  spinal anesthesia ) include:


Some less invasive procedures are available according to patients' preferences and co-morbidities. These are performed as  outpatient procedures  with  local anesthesia .


While  herbal remedies  are commonly used, a 2016 review found the herbs studied to be no better than  placebos . [ 164 ]  Particularly, several reviews found that  saw palmetto extract , while one of the most commonly used, is no better than a placebo both in symptom relief and in decreasing prostate size. [ 165 ] [ 166 ] [ 167 ]


Globally, benign prostatic hyperplasia affects about 94 million males as of 2019 [update] . [ 3 ]


The prostate gets larger in most men as they get older. For a symptom-free man of 46 years, the risk of developing BPH over the next 30 years is 45%.  Incidence  rates increase from 3 cases per 1000 man-years at age 45–49 years, to 38 cases per 1000 man-years by the age of 75–79 years. While the  prevalence  rate is 2.7% for men aged 45–49, it increases to 24% by the age of 80 years. [ 169 ]


Boar taint  is the offensive odor or taste that can be evident during the cooking or eating of  pork  or pork products derived from non-castrated male pigs once they reach puberty. Boar taint is found in around 20% of entire male finishing pigs.  Skatole  may also be detected in  gilts , but this is linked with fecal contamination of the skin. Studies show that about 75% of consumers are sensitive to boar taint, leading pork producers to control this in order to maximize profits. [ 1 ]


Boar taint is caused by the accumulation of two compounds –  androstenone  and skatole – in the fat of male pigs.  Androstenone (a male pheromone) is produced in the testes as male pigs reach puberty and gives the meat a urine or sweat flavour, while skatole (a byproduct of intestinal bacteria, or bacterial metabolite of the amino acid  tryptophan ) is produced in both male and female pigs and gives the meat a 'fecal' flavour. However, levels are much higher in intact boars, because testicular steroids inhibit its breakdown by the liver. As a result, skatole accumulates in the fat of male pigs as they mature.


For centuries, pigs have been  castrated  to prevent boar taint. Castration rates vary from country to country, and most still do not use  anesthesia  or  analgesia  when castrating pigs. Commercial farms that do castrate will do so in the pig's first week of life.


Another possible method to control boar taint is to use  sex sorted semen  for artificial insemination so as to produce mostly female offspring. This method has been successfully used in cattle breeding, but the technique is still under research and no economical or practical solution yet exists in pig production.


As castration has received criticism in recent years, for welfare reasons, some producers and producer associations are seeking alternative methods to control boar taint. [ 2 ]  Some producers are breeding out the taint and avoiding the few breeds of pigs that are high in taint.  Yorkshire ,  Hampshire  and other lighter-colored pigs are known to be particularly low in the androstenone-based taint while  Duroc pigs  are high in the taint. [ citation needed ]


Vaccination  against boar taint with  Improvac , [ 3 ] : 503   which has been used in Australia and New Zealand since 1998, is a solution [ 2 ] [ 4 ] [ 3 ] : 503  [ 5 ]  that uses the pig's immune system to control boar taint. The use of the vaccine is claimed to be as simple and reliable as physical castration in controlling boar taint. It can be administered by trained farm personnel and enables the production of pork meat that is claimed to be of high quality and to be safe for consumers to eat. [ 6 ]


The vaccine works by stimulating the pig's immune system to produce specific antibodies against  gonadotropin-releasing hormone  (GnRH). This temporarily inhibits testes function and thus stops the production and accumulation of boar taint–causing compounds.


By stimulating production of antibodies specific to GnRH, the vaccine stops the chain of events that lead to the release of testosterone and other steroids from the testes, including androstenone, one of the two causes of boar taint. The other major taint-causing compound, skatole, is also eliminated, because the lower steroid levels allow the liver to more efficiently metabolise it.


Each pig must be immunised twice to successfully control boar taint. The timing of the first dose is relatively flexible, but there must be a minimum of four weeks between the two doses, with the second taking place four to six weeks before slaughter. After the second dose, the boar's testicles stop growing. The handler should be trained in the use of the vaccine and the vaccinator with enhanced safety features.


The vaccine is claimed to offer an animal-friendly and a more environmentally sustainable solution to boar taint, and to allow getting benefits of natural boar growth while preserving eating quality. [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ] [ 12 ]  However concerns about the effect of the drugs on animal and consumer health have been expressed. [ 13 ]


The vaccine will work in multiple mammalian species and is commonly used for contraceptive purposes in zoo animals and  oestrus  suppression in horses. The vaccine would also work to temporarily prevent sexual function in humans, but no cases of this have ever been recorded.  [ citation needed ]


Capacitation  is the penultimate [ 1 ]  step in the maturation of  mammalian   spermatozoa  and is required to render them competent to  fertilize  an  oocyte . [ 2 ]  This step is a biochemical event; the sperm move normally and look mature prior to capacitation.
 In vivo , capacitation occurs after  ejaculation , when the spermatozoa leave the vagina and enter the upper  female reproductive tract . The  uterus  aids in the steps of capacitation by secreting sterol-binding  albumin ,  lipoproteins , and  proteolytic  and  glycosidasic   enzymes  such as heparin.


For purposes of  in vitro  fertilization, capacitation occurs by incubating spermatozoa that have either undergone ejaculation or have been extracted from the  epididymis  and incubated in a defined medium for several hours. There are different techniques to perform the capacitation step: simple washing, migration (swim-up), density gradients, and filter. The objective is to isolate as many motile spermatozoa as possible and to eliminate non-motile or dead spermatozoa. After either  in vivo  or  in vitro  capacitation the sperm must undergo the final maturation step, activation, involving the  acrosome reaction .


Non-mammalian spermatozoa do not require this capacitation step and are ready to fertilize an oocyte immediately after release from the male.


Capacitation has two effects: destabilisation of the acrosomal sperm head membrane which allows it to penetrate the outer layer of the egg, and chemical changes in the tail that allow a greater mobility in the sperm. [ 3 ]  The changes are facilitated by the removal of  sterols  (e.g.  cholesterol ) and non-covalently bound epididymal/seminal  glycoproteins . The result is a more fluid membrane with an increased permeability to Ca 2+  ion.


An influx of Ca 2+  produces increased intracellular  cAMP  levels and thus, an increase in motility.  Hyperactivation  coincides with the onset of capacitation and is the result of the increased Ca 2+  levels. It has a synergistic stimulatory effect with adenosine that increases  adenylyl cyclase  activity in the sperm. [ citation needed ]


The tripeptide  fertilization promoting peptide  (FPP) is essential for controlling capacitation. FPP is produced in the  prostate gland  as a component of the seminal fluid. FPP comes into contact with the spermatozoa during ejaculation, as the sperm and seminal fluid mix. High levels of active FPP prevent capacitation. After ejaculation, the concentration of FPP drops in the female reproductive tract.  [ citation needed ]


Because  assisted reproductive technologies , or ARTs, such as  in vitro  fertilization  (IVF) or  intrauterine insemination  (IUI) require the induction of sperm cell capacitation outside of normal biological parameters, numerous methods have been developed to induce this process in mammalian sperm cells. Sperm cells are harvested through ejaculation or harvested from the caudal  epididymis  and allowed to liquefy at room temperature. Capacitation can then be induced by adding media designed to mimic the electrolytic composition of the  fallopian tubes , where fertilization occurs. These media vary between species, but are saline-based and contain energy substrates such as lactate, pyruvate, and possibly glucose. A cholesterol acceptor is required to facilitate the removal of cholesterol from the sperm cell membrane, which is always albumin.  Bovine serum albumin  is typically used for  in vitro  animal studies, and  human serum albumin  (HSA) is used in human sperm capacitation induction.


Bicarbonate  is a vital component of capacitation-inducing media, as it is co-transported into the  cytosol  where it activates soluble  adenylyl cyclase  (sAC) as well as acts as a pH buffer necessary to prevent decreasing the pH in the culture, a necessary addition when incubating cells at 5% CO 2  as is generally used although not required.  Calcium chloride  is added to facilitated the influx via of calcium cations. [ 4 ] [ 5 ]  In animal models, Tyrode's albumin lactate pyruvate (TALP) medium is typically used as a base, which contains each of these components. In humans, human tubal fluid (HTF) is used.


These media can be supplemented with other chemicals to induce hyperactivated sperm motility and/or the acrosome reaction. For animal in vitro fertilization,  caffeine  at 5 mM concentration is a strong inducer of sperm capacitation  in vitro . [ 6 ] [ 7 ]  Calcium  ionophores  are also ideal to induce capacitation. [ 7 ]  Adding heparin to capacitation inducing medium mimics the secretion of heparin-like  gycosaminoglycans  (GAGs) near the oocyte and initiates the acrosome reaction. This effect is magnified when adding  lysophosphatidylcholine  (LC) in conjunction with heparin. [ 8 ]   Catecholamines  such as  norepinephrine  at low concentrations have been shown to assist in acrosome reaction induction. [ 9 ]


The traditional methods to perform  in vitro  capacitation are:


However, nowadays there are new techniques which surpass these ones. For instance, we have PICSI, MACS or microfluidic chips.


Numerous methods have been developed to assess the degree to which sperm cells are undergoing capacitation in vitro. Computer-aided sperm analysis (CASA) was developed in the 1980s for measuring sperm kinematics. [ 11 ]  CASA uses  phase-contrast microscopy  combined with sperm tracking software to analyze sperm motility parameters. [ 11 ]  Certain parameters such as curvilinear velocity (VCL), straightline velocity (VSL), average path velocity (VAP), and the amplitude of lateral head displacement (ALH) have been shown to be positively correlated with the acquisition of fertilization competency and are thus used to identify hyperactive sperm cell motility. [ 12 ]


While motility measurements are critical for identifying the presence of hyperactive motility, additional methods have been developed to identify the occurrence of the acrosome reaction. A simple method uses Coomassie brilliant blue G250 to stain cells, providing visual evidence of intact or reacted acrosomes. [ 13 ]  More advanced techniques employ fluorescent or  electron microscopy  methods.  Fluorescein -conjugated  Peanut agglutinin  (FITC-PNA) or  Pisum sativum   agglutinin  (FITC-PSA) can be used to fluorescently tag the acrosome of sperm cells, which can be then used to assess the status of the acrosome using a  fluorescent microscope . [ 14 ] [ 15 ] [ 16 ]


The discovery of this process was independently reported in 1951 by both  Min Chueh Chang [ 17 ]  and  Colin Russell Austin . [ 18 ] [ 19 ]


Castration  is any action,  surgical ,  chemical , or otherwise, by which a  male  loses use of the  testicles : the male  gonad . Surgical castration is bilateral  orchiectomy  (excision of both testicles), while  chemical castration  uses  pharmaceutical drugs  to deactivate the testes. Castration causes  sterilization  (permanently preventing the castrated person or animal from  reproducing ); it also greatly reduces the production of  hormones , such as  testosterone  and  estrogen . Surgical castration in animals is often called  neutering .


Castration of animals  is intended to favor a desired development of the animal or of its habits, as an  anaphrodisiac  or to prevent  overpopulation . The parallel of castration for female animals is  spaying . Castration may also refer medically to  oophorectomy  in female humans and animals.


The term  castration  may also be sometimes used to refer to  emasculation  where both the testicles  and  the penis are removed together. In some cultures, and in some translations, no distinction is made between the two.


Castration may have arisen in the Neolithic period in response to animal husbandry, rising populations and population specialisation. [ 1 ]


Either surgical removal of both testicles or  chemical castration  may be carried out in the case of  prostate cancer . [ 2 ]   Testosterone -depletion treatment (either surgical removal of both testicles or chemical castration) is used to slow down the cancer. Surgical removal of one or both testicles known as  orchidectomy  is the most common treatment for testicular cancer. [ 3 ]


Castration has also been used in the United States for  sex offenders  as a way of avoiding incarceration. [ 4 ]  It can greatly reduce sex drive or interest in those with sexual drives, obsessions, or behaviors, or any combination of those that may be considered deviant.


Involuntary castration appears in the history of warfare, sometimes used by one side to torture or demoralize their enemies. [ 5 ]


Over the 13 centuries of the  Arab slave trade  in Africa, unknown numbers of Africans were enslaved and shipped to the Middle East.


"The Caliphate in Baghdad at the beginning of the 10th Century had 7,000 black eunuchs and 4,000 white eunuchs in his palace." [ 6 ]  The Arab slave trade typically dealt in the sale of castrated male slaves. Black boys at the age of eight to twelve had their penises and scrota completely amputated. Reportedly, about two out of three boys died, but those who survived drew high prices. [ 7 ]


The employment or enslavement of eunuchs (castrated men) was practiced in classical and Roman antiquity and continued into the Middle Ages. In the 10th century, slave traders in Verdun in France and in Becâne ( Pechina ), Spain, castrated captives who were then enslaved as harem attendants in  Al-Andalus . [ 8 ]


Edward Gibbon 's  Decline and Fall of the Roman Empire  reports castration of defeated  Byzantine Greeks  at the hands of the  Frankish  marquis  Theobald  of Camerino and Spoleto in the course of 10th-century wars in Italy. [ 9 ]  Gibbon also alludes to a 12th-century incident set out in  William Fitzstephen 's  Vita Sancti Thomae  ( Life of  St. Thomas ) in which  Geoffrey of Anjou  castrated the members of the cathedral chapter of  Sens  as a punishment for disobedience. [ 10 ] [ 11 ]  In the medieval  kingdom of Georgia , the 12th-century  pretender   Demna  was castrated by his uncle  George III of Georgia  to ensure the supremacy of George's branch of the family. [ 12 ]  Another victim of castration was the 12th-century medieval French philosopher, scholar, teacher, and (later) monk  Pierre Abélard . He was castrated by relatives of his lover,  Héloïse . [ 13 ]   Bishop Wimund , a 12th-century English adventurer and invader of the Scottish coast, was blinded and castrated after losing a power struggle. [ 14 ]  In medieval England, men found guilty of  high treason  were  hanged, drawn and quartered , which often included  emasculation  (removal of the genitalia). [ 15 ]


Wim Deetman  was criticized by the Dutch parliament for excluding evidence of castration [ 16 ]  in his report on sexual abuse by the Roman Catholic Church, where ten children were allegedly "punished" by castration in the 1950s for reporting sexual abuse by Roman Catholic priests. The Deetman Commission had rejected it as the person who reported the incident admitted it was speculative.


In Spain, a law against castration was used to deny sex-reassignment surgery to transgender people until the Penal Code was reformed in 1983. [ 17 ]


According to legend, during the reign of the legendary Emperor Shun and Yu in China, in 2281 BC, castration was passed into law as a punishment, remaining so until the reign of  Gaozu of Tang  (618–626 AD). However, it was still practiced after his reign. [ 18 ]  According to historians, it was incorporated into Chinese law during the Zhou dynasty. [ 19 ]  It was one of the five physical punishments that could be legally inflicted on criminals in China. [ 20 ]


Records of castrations in China date to the  Shang dynasty  ( c.  1700 –1050 BC), when the Shang kings castrated prisoners of war. [ 21 ] [ 22 ]


During the reign of  Mu  of the  Zhou dynasty  (10th c. BC) the Minister of Crime, Marquis Lu, reformed the law in 950 BC to make it easier for people to be sentenced to castration instead of death. [ 23 ]  As long as the practice existed in China, not only were the testicles removed but castration included the severing of one's entire genitalia. Both organs were cut off with a knife at the same time. [ 24 ]


Men were castrated and made into state slaves during the  Qin dynasty  (221–206 BC) to perform forced labor for projects such as the  Terracotta Army . [ 25 ]  The Qin government confiscated the property and enslaved the families of rapists who received castration as a punishment. [ 26 ]  Men punished with castration during the  Han dynasty  were also used as slave labor. [ 27 ]


In the Han dynasty (206 BC–220 AD), castration continued to be used as a punishment for various offences. [ 28 ] [ 29 ]  Chinese historian  Sima Qian  was castrated by order of the Han Emperor of China for dissent. [ 30 ]  In another incident multiple people, including a chief scribe and his underlings, were subjected to castration. [ 31 ]


During the early part of the  Ming dynasty  (1368–1644 AD), China demanded eunuchs to be sent as tribute from  Korea . Some of them oversaw the Korean concubines in the harem of the Chinese Emperor. [ 32 ] [ 33 ]


When the Chinese overthrew Mongol rule, many Mongol captives were castrated and turned into eunuchs. [ 34 ]  When the Ming army finally captured  Yunnan  from Mongols in 1382, thousands of prisoners were killed and, according to the custom in times of war, their young sons—including  Zheng He —were castrated. [ 35 ] [ 36 ]


During the  Miao Rebellions (Ming dynasty) , Chinese commanders castrated thousands of  Miao  boys when their tribes revolted, and then distributed them as eunuch slaves as gifts to various officials. [ 36 ]


At the end of the Ming dynasty, there were about 70,000 eunuchs (宦官  huànguān , or 太監  tàijiàn ) employed by the emperor, with some serving inside the  Forbidden City .


The last imperial eunuch in China was  Sun Yaoting  who died in 1996.


The  Khitan people  adopted the practice of using eunuchs from the Chinese and the eunuchs used were non-Khitan prisoners of war. The Khitan were a  nomadic   Mongolic people  and originally did not have eunuchs as part of their culture. [ 37 ]  When the Khitan founded the  Liao dynasty  they developed a  harem  system with concubines and wives and adopted eunuchs as part of it. All of the eunuchs captured were ethnic Chinese from the  Central Plains  that came from two sources. The Khitan captured Chinese people who were already eunuchs at the Jin court when they invaded the  Later Jin . Another source was during their war with the Chinese  Song dynasty : the Khitan would raid China, capture Han Chinese boys as prisoners of war and emasculate them to become eunuchs. The emasculation of captured Chinese boys guaranteed a continuous supply of eunuchs to serve in the Liao dynasty harem. The Empress Dowager  Xiao Chuo  (Chengtian) played a large role in the raids to capture and emasculate the boys. [ 38 ]


Chengtian took power at age 30 in 982 as a regent for her son. Some reports suggest that she personally led her own army against the Song Chinese in 986. Her army defeated them in battle, [ 39 ]  fighting the retreating Chinese army. She then ordered the castration of around 100 ethnic  Chinese  boys she had captured in China, supplementing the Khitan's supply of eunuchs to serve at her court, among them was  Wang Ji'en . The boys were all under ten years old and were selected for their good looks. [ 40 ] [ 41 ]


The  History of Liao  遼史 described and praised Empress Chengtian's capture and mass castration of the Chinese boys in a biography on Wang Ji'en. [ 42 ]


Some legends say that the Mongol  Genghis Khan  was castrated by a Tangut princess using a knife, who wanted revenge against his treatment of the Tanguts and to stop him from raping her. [ 43 ]


During the  Qing dynasty  (1644–1911 AD), the sons and grandsons of the rebel  Yaqub Beg  in China were all sentenced to castration. Surviving members of Yaqub Beg's family included his four sons, four grandchildren (two grandsons and two granddaughters), and four wives. They either died in prison in  Lanzhou , Gansu, or were killed by the Chinese. His sons Yima Kuli, K'ati Kuli, Maiti Kuli, and grandson Aisan Ahung were the only survivors in 1879. They were all underage children, and put on trial, sentenced to an agonizing death if they were complicit in their father's rebellious "sedition", or if they were innocent of their fathers crimes, were to be sentenced to castration and serving as  eunuch  slaves to Chinese troops, when they reached 11 years old, and handed over to the Imperial Household to be executed or castrated. [ 44 ] [ 45 ] [ 46 ]  Although some sources assert that the sentence of castration was carried out, official sources from the US State Department and activists involved in the incident state that Yaqub Beg's son and grandsons had their sentence commuted to life imprisonment with a fund provided for their support. [ 47 ] [ 48 ] [ 49 ]


The eunuchs of Korea, called  Naesi  (내시, 內侍), were officials to the king and other royalty in traditional Korean society. The first recorded appearance of a Korean eunuch was in  Goryeosa  ("History of Goryeo"), a compilation about the  Goryeo  period. In 1392, with the founding of the  Joseon dynasty , the  Naesi  system was revised, and the department was renamed the "Department of  Naesi " (내시부, 內侍府). [ 50 ]


The  Naesi  system included two ranks, those of  Sangseon  (상선, 尙膳, "Chief of  Naesi "), who held the official title of senior second rank, and  Naegwan  (내관, 內官, "Common official  naesi "), both of which held rank as officers. 140  naesi  in total served the palace in Joseon dynasty period. They also took the exam on  Confucianism  every month. [ 50 ]  The  naesi  system was repealed in 1894 following  Gabo reform . [ citation needed ]


According to legend, castration consisted of daubing a boy's  genitals  with human  feces  and having a dog bite them off. [ 51 ]  During the  Yuan dynasty , eunuchs became a desirable commodity for  tributes , and dog bites were replaced by more sophisticated surgical techniques. [ 52 ]


The Vietnamese adopted the eunuch system and castration techniques from China. Records show that the Vietnamese performed castration in a painful procedure by removing the entire genitalia with both penis and testicles being cut off with a sharp knife or metal blade. The procedure was agonizing since the entire penis was cut off. [ 53 ]  The young man's thighs and abdomen would be tied, and others would pin him down on a table. The genitals would be washed with pepper water and then cut off. A tube would be then inserted into the urethra to allow urination during healing. [ 54 ]  Many Vietnamese eunuchs were products of self-castration in order to gain access to the palaces and power. In other cases, they might be paid to become eunuchs. They served in many capacities, from supervising public works, to investigating crimes, to reading public proclamations. [ 55 ]


Lý Thường Kiệt  was a prominent eunuch general during the  Lý dynasty  (1009–1225).


The  Trần dynasty  sent Vietnamese boy eunuchs as tribute to Ming dynasty China several times, in 1383, 1384 and 1385 [ 56 ]  Nguyen Dao, Nguyen Toan, Tru Ca, and Ngo Tin were among several Vietnamese eunuchs sent to China. [ 57 ]


During the  Fourth Chinese domination of Vietnam , the Ming Chinese under the  Yongle Emperor  castrated many young Vietnamese boys, choosing them for their handsomeness and ability, and brought them to Nanjing to serve as eunuchs. Among them were the architect-engineer  Nguyễn An [ 58 ]  and  Nguyen Lang  (阮浪). [ 59 ]  Vietnamese were among the many eunuchs of different origins found at Yongle's court. [ 60 ]  Among the eunuchs in charge of the Capital Battalions of  Beijing  was Xing An, a Vietnamese. [ 61 ]


In the  Lê dynasty  the Vietnamese Emperor  Lê Thánh Tông  was aggressive in his relations with foreign countries including China. A large amount of trade between Guangdong and Vietnam happened during his reign. Early accounts recorded that the Vietnamese captured Chinese whose ships had blown off course and detained them. Young Chinese men were selected by the Vietnamese for castration to become eunuch slaves to the Vietnamese. It has been speculated by modern historians that the Chinese who were captured and castrated by the Vietnamese were involved in trade between China and Vietnam instead of actually being blown off course by the wind and they were punished as part of a crackdown on foreign trade by Vietnam. [ 62 ]


Several Malay envoys from the  Malacca sultanate  were attacked and captured in 1469 by the Lê dynasty of Annam (Vietnam) as they were returning to Malacca from China. The Vietnamese enslaved and castrated the young from among the captured. [ 56 ] [ 63 ] [ 64 ]


A 1472 entry in the  Ming Shilu  reported that when some Chinese from  Nanhai county  escaped back to China after their ship had been blown off course into Vietnam, where they had been forced to serve as soldiers in Vietnam's military. The escapees also reported that they found out up to 100 Chinese men remained captives in Vietnam after they were caught and castrated by the Vietnamese after their ships were blown off course into Vietnam. The Chinese Ministry of Revenue responded by ordering Chinese civilians and soldiers to stop going abroad to foreign countries. [ 65 ] [ 66 ] [ 67 ] [ 68 ]  China's relations with Vietnam during this period were marked by the punishment of prisoners by castration. [ 69 ] [ 70 ]


A 1499 entry in the Ming Shilu recorded that 13 Chinese men from  Wenchang  including a young man named Wu Rui were captured by the Vietnamese after their ship was blown off course while traveling from  Hainan  to  Guangdong 's Qin subprefecture ( Qinzhou ), after which they ended up near the coast of Vietnam, during the  Chenghua Emperor 's rule (1447–1487). Twelve of them were enslaved to work as agricultural laborers, while the youngest,  Wu Rui  (吳瑞) was selected for castration since he was the only young man and he became a eunuch attendant at the  Vietnamese imperial palace in Thang Long . After years of service, he was promoted at the death of the Vietnamese ruler in 1497 to a military position in northern Vietnam. A soldier told him of an escape route back to China and Wu Rui escaped to  Longzhou . The local chief planned to sell him back to the Vietnamese, but Wu was rescued by the  Pingxiang  magistrate and then was sent to Beijing to work as a eunuch in the palace. [ 71 ]


The  Đại Việt sử ký toàn thư  records that in 1467 in An Bang province of Dai Viet (now  Quảng Ninh Province ) a Chinese ship blew off course onto the shore. The Chinese were detained and not allowed to return to China as ordered by Le Thanh Tong. [ 72 ]  This incident may be the same one where Wu Rui was captured. [ 73 ]


In the  Nguyễn dynasty  the poet  Hồ Xuân Hương  mocked eunuchs in her poem as a stand-in for criticizing the government. [ 74 ]


Commoners were banned from undergoing castration in Vietnam; only adult men of high social rank could be castrated. Most eunuchs were born as such with a congenital abnormality. The Vietnamese government mandated that boys born with defective genitalia were to be reported to officials, in exchange for the town being freed from mandatory labor requirements. The boy would have the option of serving as a eunuch official or serving the palace women when he became ten years old. [ 75 ]  This law was put in place in 1838 during the Nguyễn dynasty. [ 76 ]  The only males allowed inside the Forbidden City at  Huế  were the Emperor and his eunuchs. [ 77 ]


The presence of eunuchs in Vietnam was used by the French colonizers to degrade the Vietnamese. [ 78 ]


In 1778,  Thomas Jefferson  wrote a bill in Virginia reducing the punishment for rape, polygamy, or sodomy from death to castration. [ 79 ]  Over the years, several U.S. states have passed laws regarding chemical castration for sex offenders but not one state has mandatory castration. In 2016, Alabama lawmaker  Steve Hurst  proposed a bill requiring certain sex offenses to require the perpetrator be castrated prior to their release from state custody. [ 80 ]


A 1969 study found that men institutionalized at the same facility in Kansas lived an extra 14 years, on average, if they were castrated. [ 81 ]


In 1983, Judge C. Victor Pyle sentenced three men convicted of rape to choose between 30 years in prison or castration. [ 82 ]  The South Carolina Supreme Court ruled that the castration option would be cruel, however, and the men were sentenced to prison. [ 83 ] [ 84 ]


Chemical or surgical castration is practiced in many countries for people convicted of sex crimes as a prerequisite for their release from prison. The castration may be voluntary or mandated. The assumption is that it prevents future crimes. Reports are available from American and European countries for over 80 years (chemical for circa 30). [ 85 ]  The effectiveness and ethics of this treatment are heavily debated.


A  temporary  "chemical castration" has been studied and developed as a preventive measure and  punishment  for several repeated  sex crimes , such as rape or other  sexually related violence . [ 86 ] [ 87 ]  Where homosexuality has been criminalised or treated as a mental illness, chemical castration has been used on gay men, as in the case of  Alan Turing . [ 88 ]


In modern times, the  Czech Republic  practices surgical castration of convicted sex offenders. According to the reports compiled by Council of Europe, a human-rights forum, the central European country physically castrated at least 94 prisoners in the 10 years up to April 2008. The Czech Republic defends this procedure as voluntary and effective. [ 89 ]  According to Dr. Martin Hollý, director of the Psychiatric Hospital Bohnice in Prague, none of the nearly 100 sex offenders who had been physically castrated had committed further offences. [ 90 ]  One serial offender stated that being castrated was the "best decision" he ever made: "On the one hand you have to protect the potential victims and on the other hand I wanted to be protected from myself, I wanted to live like a normal person." [ 91 ]  Don Grubin, a professor at  Newcastle University 's Institute of Neuroscience who also runs a chemical castration program backed by the UK's  Ministry of Justice , was initially opposed to physical castration. After visiting the Czech Republic, however, he agreed that some form of castration might be of benefit to some sex offenders. [ 91 ] [ 92 ]


In 2020, the  Pakistani -controlled section of  Kashmir  passed a bill allowing for convicted child sex abusers to be chemically or surgically castrated. [ 93 ]


In 2020, a motion calling for surgical castration of convicted rapists was defeated in the  Nigerian House of Representatives . [ 94 ]  However, there remains support for the policy. [ 95 ] [ 96 ]


In 2024, Louisiana became the first U.S. state to allow judges to impose castration on sex offenders. [ 97 ]  Previously, in several states, convicted offenders could choose castration, including where it was a prerequisite for parole. However, should the person choose to remain in prison, they would not be forced to be castrated. [ 98 ]


Some criminologists argue that the reported lower recidivism rates in castrated male sex offenders compared to non-castrated ones does not conclusively prove that it is a biological effect of castration, but might be explained by other factors. One suggested factor from  game theory  is that men who are willing to accept castration to get a shorter prison sentence are those who value freedom from prison higher than men who are not willing to pay the price for freedom in the form of their testicles. This hypothesis could explain their apparent lower recidivism as a result of working harder to conceal the evidence for their crimes, and argue that their parole is a danger of releasing offenders who only hide their crimes more efficiently and are not any less likely to commit new crimes. These criminologists also argue that police investigators treating castrated men as less likely to reoffend than non-castrated men may cause an investigation bias and  self-fulfilling prophecy . [ 99 ] [ 100 ]


Castration and other forms of  male genital mutilation  have been practiced against enemy soldiers and civilians from ancient times to the twenty-first century. [ 101 ]  Sometimes it is practiced against living boys and men and other times against corpses. [ 101 ]


The castration of defeated enemies and the taking of body parts as trophies were traditional in  Ethiopia , [ 102 ]  and Ethiopian forces practiced castration and emasculation during the  Second Italo-Ethiopian War  (1935–1937). [ 103 ] [ 104 ]  Italian aviator  Tito Minniti  was allegedly one victim of this practice. [ 105 ]


One British RAF officer, G. C. Gardiner DSO DFC, is recorded as having been castrated after a crash landing in Syria. [ 106 ]  During the  Mau Mau uprising , there were reported instances of British security forces castrating Kenyan detainees in  internment camps . [ 101 ]


A video released during the  2022 Russian invasion of Ukraine  appeared to show Russian soldiers castrating a Ukrainian captive with a  box cutter . This led to a wave of international condemnation against the Russian military for its use of torture in wartime. [ 107 ]  Many other cases of Russian troops castrating Ukrainian prisoners of war have also emerged. [ 108 ] [ 109 ] [ 110 ] [ 111 ]  According to the  prosecutors , 101 cases of sexual violence against Ukrainian men by occupying Russian forces have been recorded, including 50 in the  Kherson  region. But this is almost certainly a vast undercount, since experts say men are often reluctant to report sexual violence. [ 112 ]


When Ukrainian cities were liberated, numerous abuses by Russian forces were exposed, including castrations, in attempts to terrorize and demoralize the Ukrainian population to break their will to fight. [ 113 ]


In Europe, when women were not permitted to sing in church or cathedral choirs in the Roman Catholic Church, boys were castrated to develop a special high  voice  and to prevent their voices breaking at  puberty . The first documents mentioning  castrati  are Italian church records from the 1550s. [ 114 ]  In the baroque and classical music eras these singers were highly appreciated by opera composers as well.  Mozart 's  Exultate Jubilate ,  Allegri 's  Miserere  and other pieces from this period now sung by  sopranos  and countertenors were written for  castrati . Some of the alto parts of  Handel 's  Messiah  were first sung by a  castrato .  Castrati  include  Farinelli ,  Senesino ,  Carestini , and  Caffarelli . The last true  castrato  was  Alessandro Moreschi  (1858–1922) who served in the  Sistine Chapel Choir . [ 115 ]  It was not until the late 19th century that the Roman Catholic Church officially condemned the production of  castrati . In modern times, the Mexican  Javier Medina  is the only professional opera singer who can perform as a castrato, since he had an involuntary chemical castration, as a result of a cancer treatment that he had before he reached puberty. [ 116 ]


In South Asia, many  hijras  live in well-defined, organized, all-hijra communities, led by a guru. The power of the hijras as a sexually ambiguous category can only be understood in the religious context of Hinduism. In some Hindu beliefs, ritual, and art, the power of the combined man/woman, or androgyne, is a frequent and significant theme.  Bahuchara Mata , the main object of hijra veneration, is specifically associated with  transgender  topics. [ 117 ]


In the  Gospel of Matthew ,  Jesus of Nazareth  mentions castration in a discussion about avoiding adultery and divorce that some are involuntarily castrated or born that way, while some others "make themselves eunuchs" willingly out of a desire to be chaste ( Matthew 19:1–12 ). Given Jesus' frequent use of metaphor and hyperbole, e.g.  Luke 9:62 , the Catholic Church has broadly discouraged any understanding of this passage as recommending literal "self-castration". That is consistent with Jesus' claims (as a rabbi) to uphold the Law given to Moses, e.g.  Matthew 5:17 , a Law which also discouraged literal castration  Deut 23:1 . However, in his own comments Jesus had no condemnation for any of the above. In  Acts 8:34–8:39 , a eunuch is baptized by  Philip the Evangelist , demonstrating acceptance of castrated individuals in his church.


The first canon of the  First Council of Nicaea  in 325 AD forbade clergy members to voluntarily castrate themselves "when in perfect health", but freely accepted those who had been either castrated by others against their will, castrated due to a medical sickness or necessity, or those born as eunuchs.


Paul, arguing against self-righteousness regarding  circumcision  in  Galatians 5:12 , says "As for those agitators, I wish they would go the whole way and emasculate themselves!" ( NIV )


Well-known Christian eunuchs (or alleged eunuchs) include:


Judaism  strictly forbids the castration of either humans or animals. [ 120 ]  Deuteronomy 23:1 expels castrated men from the assembly of Israel; they are forbidden to marry or if married must divorce from their wives (though permitting the castrated to marry or remain married to female converts to Judaism). The laws of castration also apply to cases of irreversible or un-reversed vasectomy and all other cases where the flow of sperm is known to have been placed into a permanent state of dysfunction with either no hope or no desire to take the steps to repair. [ 121 ]


Isaiah 56:3–5 references in a positive welcoming manner eunuchs who follow after God's laws. "Neither let the son of the stranger, that hath joined himself to the LORD, speak, saying, The LORD hath utterly separated me from his people: neither let the eunuch say, Behold, I am a dry tree. For thus saith the LORD unto the eunuchs that keep my sabbaths, and choose the things that please me, and take hold of my covenant; Even unto them will I give in mine house and within my walls a place and a name better than of sons and of daughters: I will give them an everlasting name, that shall not be cut off."


According to  Rashi , Kham (Ham) castrated his father Noah and was cursed as a result. [ 122 ]


In Judaism, castrated animals are deemed unfit for  sacrifice  in the  Temple in Jerusalem  ( Lev 22:24 ). Castrated members of the priestly caste are forbidden to enter certain parts of the temple, to approach the altar, or to make sacrifices, although they could eat their share of the offerings and receive the priestly and Levite gifts (Lev. 21:16–24).


The  Muslim conquest of Persia  as well as later  conquests in the Byzantine Empire  and  India  brought them into contact with eunuchs. By the eighth century, the palaces of the caliphs were staffed with many eunuch slaves which sold at a premium. A regular trade in eunuchs developed with slaves being taken to locations in Spain or Africa to be castrated, as the practice of castration was forbidden for Muslims. Eunuchs were used as harem supervisors, as mediators or servile roles, but they could also rise to be trusted advisors or military commanders. [ 123 ] : 75


In  Islam , castration is considered a sin and strictly forbidden, whether one performs it on oneself or on another. [ 124 ]  In the  history of slavery in the Muslim  world, a fair proportion of male slaves were imported as eunuch. Levy states that according to the Quran and Islamic traditions, such emasculation was objectionable. Some jurists such as  al-Baydawi  considered castration to be mutilation, stipulating laws to prevent it. However, in practice, emasculation was frequent. [ 125 ]  In eighteenth-century Mecca, the majority of eunuchs were in the service of the mosques. [ 126 ]


A subject of castration who is altered before the onset of puberty will retain a high voice, as well as the effects of hypogonadism, which include non-muscular build, an infantile penis, a lack of a beard, more developed subcutaneous fat. He may be taller than average, with long limbs, so called "eunuchoid appearance", as the production of sex hormones in puberty—more specifically, estrogen via aromatization of testosterone—stops long bone growth in a process called osseous maturation. The subject may lack the male distribution of axillary hair, and may develop  pubic hair  distributed in female pattern. They may have a low sex drive or none at all. [ 127 ]


Castration stops the progression of  male pattern baldness . However, hair regrowth – if it occurs at all – may be limited to hair that was lost shortly before castration. [ 128 ]


Historically, many eunuchs who additionally underwent a  penectomy  reportedly had urinary incontinence associated with the removal of the penis. [ 129 ]


A study of 81 historical eunuchs in Korea's royal court found a 14- to 19-year increase in lifespan compared to intact men of similar socioeconomic background; these eunuchs had a  centenarian  rate of over 3%. [ 130 ]


In the case of chemical castration, ongoing regular injections of  anti-androgens  are required. Chemical castration does not actually remove the testicles or ovaries of the subject, [ 131 ]  nor is it a form of  sterilization . [ 132 ]


With the advent of chemical castration, physical castration in humans has been widely superseded, [ 133 ]  though some have undergone the procedure voluntarily. [ 134 ]


Humans commonly castrate domestic animals not intended for breeding.
Domestic animals are usually castrated to avoid unwanted or uncontrolled  reproduction ; to reduce or prevent other manifestations of  sexual behaviour  such as defending the herd from humans and other threats, or intra-herd aggression (e.g. fighting between groups of entire (uncastrated) males of a species); or to reduce other consequences of sexual behavior that may make animal husbandry more difficult, such as boundary/fence/enclosure destruction when attempting to get to nearby females of the species.


Male horses are usually castrated ( gelded ) using  emasculators , because  stallions  are rather aggressive and troublesome. The same applies to male  mules , although they are sterile. Male cattle are castrated to improve fattening and docility in feedlots or for use as  oxen .
 Breeding  individuals are kept  entire  and used for breeding: they may fetch higher prices when sold.


Livestock may be castrated when used for food to prevent indiscriminate breeding, control aggression, and improve meat and carcass quality. [ 135 ]  In  domestic pigs  the undesirable odour or taint of uncastrated males, called  boar taint , is caused by  androstenone  and  skatole  concentrations stored in the fat tissues of the animal after sexual maturity. [ 136 ]  Boar taint is only found in a small minority of pigs and can be controlled through breeding selection, diet and management. [ 137 ]  It is released when the fat is heated and has a distinct odor and flavor that is widely considered unpalatable to consumers. [ 138 ]  Consequently, in commercial meat production, male pigs are either castrated shortly after birth or slaughtered before they reach sexual maturity. [ 138 ]  Recent research in Brazil has shown that castration of pigs is unnecessary because most pigs do not have the 'boar taint'. This is due to many breeds of pigs simply not having the heredity for the boar taint and the fact that pigs are normally slaughtered at a young market weight. [ 139 ]


In the case of pets, castration is usually called  neutering , and is encouraged to prevent overpopulation of the community by unwanted animals, and to reduce certain diseases such as prostate disease and testicular cancer in male dogs (oophorectomy in female pets is often called  spaying ). Testicular cancer is rare in dogs, and also prostate problems are somewhat common in castrated male dogs when they get older. [ 140 ]  Neutered individuals have a much higher risk of developing prostate problems in comparison to intact males. Castrated male cats are more likely to develop an obstruction in their urethra, preventing them from urinating to some degree. [ 141 ]  A specialized vocabulary has arisen for neutered animals of given species:


An incompletely castrated male in livestock species (horse and cattle) is known as a  rig .


The term  stag  is used for a male animal castrated after the  secondary sex characteristics  have developed to such a point as to give him the appearance of  sexual maturity .


Methods of  veterinary  castration include instant  surgical  removal, the use of an  elastrator  tool to secure a band around the testicles that disrupts the blood supply, the use of a  Burdizzo  tool or emasculators to crush the  spermatic cords  and disrupt the blood supply,  pharmacological   injections  and  implants  and  immunological  techniques to  inoculate  the animal against his own  sexual hormones .


Certain animals, like horses and  swine , are usually surgically treated with a scrotal castration (which can be done with the animal standing while sedated and after local anesthetic has been applied), while others, like dogs and cats, are anesthetised and recumbent when surgically castrated with a pre-scrotal incision in the case of dogs, or a pre-scrotal or scrotal incision used for cats.


Castration of cattle has historically been done without pain medications. All methods of castration cause pain and distress, which can be minimized by castrating as early as possible, preferably within the first week of life. The Canadian Code of Practice for the Care and Handling of Beef Cattle requires that, as of 2018, calves older than six months be castrated using pain control. [ 142 ]


In veterinary practice an "open" castration refers to a castration in which the inguinal tunic is incised and not sutured. A "closed" castration refers to when the procedure is performed so that the inguinal tunic is sutured together after incision.


Couvade syndrome , also called  sympathetic pregnancy , is a proposed condition in which an expectant father experiences some of the same symptoms and behavior as his pregnant partner. [ 1 ]  These most often include major weight gain, altered hormone levels,  morning nausea , and disturbed  sleep  patterns. In more extreme cases, symptoms can include  labor pains , fatigue,  postpartum depression , and  nosebleeds . The labor pain symptom is commonly known as  sympathy pain .


The source of Couvade syndrome is a matter of debate. Some believe it to be a  psychosomatic  condition, while others believe it may have biological causes relating to hormone changes. [ 2 ]


The name derives from " couvade ", a class of male pregnancy rituals.


Symptoms experienced by the partner can include stomach pain, back pain, indigestion, changes in appetite, weight gain,  acne ,  diarrhea , constipation, headache, toothache, [ 3 ]   cravings , nausea, breast augmentation, breast growth, dry navel, hardening of the nipple, excessive  earwax , and  insomnia . [ 2 ]  A qualitative study listed 35 symptoms from Couvade literature, including gastrointestinal,  genitourinary , respiratory, oral or dental, stiffening of the glutes, generalized aches and pains, and other symptoms. [ 4 ]


Psychological causes suggested have included anxiety, pseudo- sibling rivalry , identification with the fetus, ambivalence about fatherhood, or  parturition envy . [ 3 ]  According to Osvlosky and Culp (1989), pregnancy causes the male counterpart to experience an emergence of ambivalence as well as a recurrence of  Oedipal conflict . [ 5 ]  In 1920s France, Couvade was claimed to be more common in conditions where sex roles are flexible and the female is of a dominant status. [ 6 ]


Studies have shown that the male partner cohabitating with a pregnant female will experience hormonal shifts in his  prolactin ,  cortisol ,  estradiol , and  testosterone  levels, typically starting at the end of the first trimester and continuing through several weeks post-partum. [ 7 ]


The  cremasteric reflex  is a superficial (i.e., close to the skin's surface)  reflex  observed in human males.


This reflex is elicited by lightly stroking or poking the superior and medial (inner) part of the thigh—regardless of the direction of stroke. [ 1 ]  The normal response is an immediate contraction of the  cremaster muscle  that pulls up the  testicle  ipsilaterally (on the same side of the body).
The reflex utilizes sensory and motor fibers from two different nerves. When the inner thigh is stroked, sensory fibers of the  ilioinguinal nerve  are stimulated. These activate the  motor fibers  of the  genital branch  of the genitofemoral nerve which causes the cremaster muscle to contract and elevate the testis. [ 2 ] : 262


In some males this reflex may be exaggerated which can occasionally lead to a misdiagnosis of  cryptorchidism . [ 3 ]


The cremasteric reflex may be absent with  testicular torsion , upper and lower motor  neuron  disorders, as well as a spine injury of L1-L2. It can also occur if the ilioinguinal nerve has accidentally been cut during a  hernia  repair. [ 4 ]


The cremasteric reflex can be helpful in recognizing testicular emergencies.  The presence of the cremasteric reflex does not eliminate testicular torsion from a differential diagnosis, but it does broaden the possibilities to include  epididymitis  or other causes of  scrotal and testicular pain .  In any event, if testicular torsion cannot be definitively eliminated in an expeditious manner, a testicular  Doppler ultrasound  or exploratory surgical intervention is usually implemented to prevent possible loss of the testicle to  necrosis . [ 5 ]


A  death erection ,  angel lust ,  rigor erectus , or  terminal erection [ 1 ]  is a post-mortem  erection , technically a  priapism , observed in the corpses of men who have been  executed , particularly by  hanging . [ 2 ]


The phenomenon has been attributed to pressure on the  cerebellum  created by the  noose . [ 3 ]  Spinal cord injuries are known to be associated with  priapism . [ 4 ]  Injuries to the cerebellum or  spinal cord  are often associated with priapism in living patients. [ 2 ]


Death by hanging, whether an execution or a  suicide , has been observed to affect the genitals of both men and women. In women, the labia and clitoris may become engorged and there may be a discharge of blood from the  vagina [ 5 ]  while in men, "a more or less complete state of erection of the  penis , with discharge of urine, mucus or prostatic fluid is a frequent occurrence ... present for one in three cases." [ 5 ]  Other causes of death may also result in these effects, including fatal gunshots to the head, damage to major blood vessels, and violent death by poisoning. A postmortem priapism is an indicator that death was likely swift and violent. [ 5 ]


Ectopic testis  is used to describe the  testis  leaving the  inguinal canal  and entering a site other than the  scrotum  ( ectopia ). Usually, it results from obstruction of the scrotal entrance or from overdevelopment and lengthening of a segment of the  gubernaculum . [ 1 ]


The positions of the ectopic testis may be: in the lower part of the abdomen, front of thigh,  femoral canal , skin of penis or behind the  scrotum . The testis is usually developed, and accompanied by an indirect  inguinal hernia . It may be divorced from the  epididymis  which may lie in the scrotum. [ 2 ] [ 3 ]


The ectopic testis can be in the perineal region, the opposite side of the  scrotum , the suprapubic region, the femoral region, or in the superficial inguinal pouch. [ 1 ]


The ectopic testis is initially normal, but if it is ignored after childhood, it may become small and soft, with  spermatogenesis  arresting and interstitial cell proliferation occurring. [ 4 ]


Ectopic testes are prone to  malignancy , epididymo-orchitis,  infertility ,  testicular torsion , and trauma. [ 5 ]


There is debate regarding the etiopathogenesis of ectopic testis. [ 6 ]  It could be caused by local mechanical barriers obstructing the normal descent, aberrant gubernacular stabilization as a result of an anomaly at its distal end, or aberrant interaction between  androgen  and  calcitonin gene-related peptide  (CGRP). [ 7 ] [ 8 ]


Diagnosis can be made based on the presence of an empty scrotum and swelling in the perineal area. Diagnosis can also be aided by palpation of the testis. Imaging methods like  tomography  and  ultrasound  might be necessary on occasion. [ 9 ]


The treatment of choice for ectopic testis is  orchiopexy . [ 9 ]


Ejaculation  is the discharge of  semen  (the  ejaculate ; normally containing  sperm ) from the  penis  through the  urethra . [ 1 ] [ 2 ] [ 3 ]  It is the final stage and natural objective of male  sexual stimulation , and an essential component of  natural conception . After forming an  erection , many men emit  pre-ejaculatory fluid  during stimulation prior to ejaculating. Ejaculation involves involuntary  contractions  of the  pelvic floor  and is normally linked with  orgasm . It is a normal part of male  human sexual development .


It can occur spontaneously during  sleep  (a  nocturnal emission  or "wet dream"). In rare cases, ejaculation occurs because of  prostatic  disease.  Anejaculation  is the condition of being unable to ejaculate.  Dysejaculation  is an ejaculation that is painful or uncomfortable.  Retrograde ejaculation  is the backward flow of semen into the  bladder  rather than out of the urethra.  Premature ejaculation  happens shortly after initiating sexual activity, and hinders prolonged  sexual intercourse . A  vasectomy  alters the composition of the ejaculate as a form of  birth control .


The normal precursor to ejaculation is  sexual arousal  of the male, leading to the  erection  of the  penis , though not all arousals or erections lead to ejaculation, and ejaculation does not require erection. Penile sexual stimulation during  masturbation  or  vaginal ,  anal ,  oral ,  manual , or  non-penetrative  sexual activity may provide the necessary stimulus for a man to achieve  orgasm  and ejaculation. With regard to  intravaginal ejaculation latency , men typically reach orgasm five to seven minutes after the start of penile-vaginal  intercourse , taking into account their desire and that of their partners, but 10 minutes is also a common intravaginal ejaculation latency. [ 4 ] [ 5 ]  Prolonged stimulation either through  foreplay  (kissing, petting and direct stimulation of erogenous zones before penetration during intercourse) or stroking (during masturbation) leads to adequate arousal and production of  pre-ejaculatory fluid . Infectious agents (including  HIV ) can be present in pre-ejaculate. [ 6 ]


Once the penis has achieved sufficient stimulation for the man to reach orgasm, ejaculation begins. [ 7 ]  The initial stage of ejaculation, called emission, is controlled by a reflex in the sympathetic spinal cord. Sperm undergo their final developmental changes within the  epididymis , where they are held until being ejaculated. [ 8 ]


Ejaculation reaches its peak in the expulsion phase, which involves the discharge of semen from the urethral opening. This ejection is driven by coordinated contractions of the pelvic muscles, including the  bulbospongiosus  and  pubococcygeus  muscles. For the semen to be expelled out of the penis, the bladder neck stays shut while the external  urethral sphincter  is relaxed. These rhythmic contractions are part of the male orgasm [ 9 ]  under the control of a  spinal reflex  at the level of the  spinal nerves  S2–4 via the  pudendal nerve . Although the external sphincter and pelvic muscles can be voluntarily controlled, any voluntary control during semen expulsion is not evident. The expulsion phase is considered an extension of the emission phase, triggered by reaching a certain level of spinal nerve activation. [ 10 ]  The typical male orgasm lasts several seconds.


Premature ejaculation  is when ejaculation occurs before it is desired. Otherwise, if a man is unable to ejaculate after prolonged sexual stimulation in spite of his desire, it is called  delayed ejaculation  or  anorgasmia . An orgasm that is not accompanied by ejaculation is known as a  dry orgasm .


At start of orgasm, pulses of semen begin to flow from the urethra, reach a peak of discharge and then diminish in flow. The typical orgasm consists of 10 to 15 contractions, although the man may not be consciously aware of so many. After the first contraction, ejaculation continues to completion involuntarily. During this stage ejaculation cannot be stopped. The rate of contractions gradually slows throughout the orgasm. Initial contractions occur on average every 0.6 seconds with an increasing increment of 0.1 seconds per contraction. Contractions of most men proceed at regular rhythmic intervals through their duration. Many men also experience irregular contractions at the end of the orgasm. [ 11 ]


Ejaculation usually begins during the first or second contraction of orgasm. For most men, the first ejection occurs during the second contraction, which is typically the largest, expelling 40% or more of total semen discharge. After this peak, the quantity of semen emitted by the penis diminishes as the contractions lessen in intensity. The muscle contractions of the orgasm can continue after ejaculation with no additional semen discharge. A small sample study of seven men showed an average of seven spurts of semen followed by an average of 10 more contractions with no semen expelled. This study also found a high correlation between number of spurts of semen and total ejaculate volume, i.e., larger semen volumes resulted from additional pulses of semen rather than larger individual spurts. [ 12 ]


Alfred Kinsey  measured the distance of ejaculation, in "some hundreds" of men. In three-quarters of men tested, ejaculate "is propelled with so little force that the liquid is not carried more than a minute distance beyond the tip of the penis." In contrast to those test subjects, Kinsey noted "In other males the semen may be propelled from a matter of some inches to a foot or two, or even as far as five or six and (rarely) eight feet". [ 13 ]   Masters and Johnson  report ejaculation distance to be no greater than 30–60 cm (12–24 in). [ 14 ]  During the series of contractions that accompany ejaculation, semen is propelled from the urethra at 500 cm/s (200 in/s), close to 18 km/h (11 mph). [ 9 ]


Most men experience a  refractory period  immediately following an orgasm, during which they are unable to achieve another erection, and a longer period before they are capable of achieving another ejaculation. During this time a male feels a deep and often pleasurable sense of relaxation, usually in the groin and thighs. The length of the refractory period varies considerably, even for a given individual. Age affects the recovery time, with younger men recovering faster than older men, though not always. [ 14 ]


Whereas some men have refractory periods of 15 minutes or more, others are able to experience sexual arousal immediately after ejaculation. A short recovery period may allow partners to continue sexual play relatively uninterrupted by ejaculation. Some men may experience their penis becoming hypersensitive to stimulation after ejaculation, which can make sexual stimulation unpleasant even while they may be sexually aroused.


Some men are able to achieve multiple orgasms, with or without the typical sequence of ejaculation and refractory period. Some of those men report not noticing refractory periods, or are able to maintain erection by "sustaining sexual activity with a full erection until they passed their refractory time for orgasm when they proceeded to have a second or third orgasm". [ 15 ]


The force and amount of semen that is ejected during ejaculation varies widely among men, containing between 0.1 and 10  milliliters [ 16 ]  (for comparison, a  teaspoon  holds 5 ml and a tablespoon, 15 ml). Adult semen volume is affected by the time that has passed since his previous ejaculation; larger semen volumes develop with longer abstinence. The duration of the stimulation leading to ejaculation can affect the volume. [ 17 ]  Abnormally low semen volume is known as  hypospermia  and abnormally high semen volume is called  hyperspermia . One possible underlying cause of low volume or complete lack of semen is  ejaculatory duct obstruction . It is normal for the amount of semen to diminish with age.


The number of sperm in an ejaculation varies widely, depending on many factors including the time since the previous ejaculation, [ 18 ]  age, stress levels, [ 19 ]  and  testosterone . Longer time of sexual stimulation immediately preceding ejaculation can result in higher concentration of sperm. [ 17 ]  An unusually low sperm count, distinguished from low semen volume, is known as  oligospermia , and the absence of any sperm from the semen is termed  azoospermia .


The first ejaculation in males often occurs about 12 months after the onset of  puberty , generally through  masturbation  or  nocturnal emission  (wet dreams). This first  semen  volume is small. The typical ejaculation over the following three months produces less than 1 ml of semen. The semen produced during early puberty is also typically clear. After ejaculation this early semen remains jellylike and, unlike semen from mature males, fails to  liquefy . A summary of semen development is shown in Table 1.


Most first ejaculations (90%) lack sperm. Of the few early ejaculations that do contain sperm, the majority of sperm (97%) lack motion. The remaining sperm (3%) have abnormal motion. [ 20 ]


As the male proceeds through puberty, the semen develops mature characteristics with increasing quantities of normal sperm. Semen produced 12 to 14 months after the first ejaculation liquefies after a short period of time. Within 24 months of the first ejaculation, the semen volume and the quantity and characteristics of the sperm match that of adult male semen. [ 20 ]


^a  Ejaculate is jellylike and fails to liquefy.
 ^b  Most samples liquefy. Some remain jellylike.
 ^c  Ejaculate liquefies within an hour.


There is a  central pattern generator  in the  spinal cord , made up of groups of  spinal interneurons , that is involved in the rhythmic response of ejaculation. This is known as the  spinal generator for ejaculation . [ 21 ]


To map the neuronal activation of the brain during the ejaculatory response, researchers have studied the expression of  c-Fos , a  proto-oncogene  expressed in neurons in response to stimulation by hormones and neurotransmitters. [ 22 ]  Expression of c-Fos in the following areas has been observed: [ 23 ] [ 24 ]


Although uncommon, some men can achieve ejaculations during masturbation without any manual stimulation. Such men usually do it by tensing and flexing their abdominal and buttocks muscles along with vigorous fantasizing. Others may do it by relaxing the area around the  penis , which may result in harder erections especially when hyper aroused. [ 25 ]  Hands-free ejaculation can also be achieved by prostate stimulation alone, either  internally  (with the use of  sex toys , fingers or performing  anal sex  or  pegging ) or externally (such as  perineum  massages), [ 26 ] [ 27 ]  although  prostate orgasms  without ejaculation (dry orgasms) are also possible. [ 28 ]


Perineum  pressing results in an ejaculation which is purposefully held back by pressing on either the perineum or the urethra to force the seminal fluid to remain inside. In such a scenario, the seminal fluid stays inside the body and goes to the  bladder . Some people do this to avoid making a mess by keeping all the semen inside. [ 29 ]  As a medical condition, it is called  retrograde ejaculation . [ 30 ]


For most men, no detrimental health effects have been determined from ejaculation itself or from frequent ejaculations, [ citation needed ]  though sexual activity in general can have health or psychological consequences. A small fraction of men have a disease called  postorgasmic illness syndrome  (POIS), which causes severe muscle pain throughout the body and other symptoms immediately following ejaculation. The symptoms last for up to a week. [ 31 ] [ 32 ] [ 33 ]  Some doctors speculate that the frequency of POIS "in the population may be greater than has been reported in the academic literature", [ 34 ]  and that many POIS sufferers are undiagnosed. [ 35 ]


It is not clear whether frequent ejaculation has any effect on the risk of  prostate cancer . [ 36 ] [ 37 ] [ 38 ]  Two large studies examining the issue were [ 39 ] [ 40 ] [ 41 ]  "Ejaculation Frequency and Subsequent Risk of Prostate Cancer" [ 42 ]  and "Sexual Factors and Prostate Cancer". [ 43 ]  These suggest that frequent ejaculation after puberty offers some reduction of the risk of prostate cancer. The US study involving 29,342 US men aged 46 to 81 years [ 42 ]  suggested that "high ejaculation frequency was related to decreased risk of total prostate cancer". [ 42 ]  An Australian study involving 1,079 men with prostate cancer and 1,259 healthy men found that "there is evidence that the more frequently men ejaculate between the ages of 20 and 50, the less likely they are to develop prostate cancer":


[T]he protective effect of ejaculation is greatest when men in their twenties ejaculated on average seven or more times a week. This group were one-third less likely to develop aggressive prostate cancer when compared with men who ejaculated less than three times a week at this age. [ 44 ]


In mammals and birds, multiple ejaculation is commonplace. [ 45 ] [ 46 ] [ clarification needed ]  During copulation, the two sides of a  short-beaked echidna 's penis are used sequentially. Alternating between the two sides allows for persistent stimulation to induce ejaculation without impeding the refractory period. [ 47 ]


In  stallions , ejaculation is accompanied by a motion of the tail known as "tail flagging". [ 48 ]  When a male  wolf  ejaculates, his final  pelvic thrust  may be slightly prolonged. [ 49 ]  A male  rhesus monkey  usually ejaculates less than 15 seconds after  sexual penetration . [ 50 ]  The first report and footage of  spontaneous ejaculation  in an aquatic mammal was recorded in a wild  Indo-Pacific bottlenose dolphin  near  Mikura Island , Japan, in 2012. [ 51 ]


In horses, sheep, and cattle, ejaculation occurs within a few seconds, but in  boars , it can last for five to thirty [ 52 ]  minutes. [ 53 ]  Ejaculation in boars is stimulated when the spiral-shaped penis interlocks with the female's cervix. [ 54 ]  A mature boar can produce 250–300 ml (8.8–10.6 imp fl oz; 8.5–10.1 US fl oz) of semen during one ejaculation. [ 53 ]  In llamas and alpacas, ejaculation occurs continuously during copulation. [ 55 ]


The semen of male dogs is ejaculated in three separate phases. [ 56 ]  The last phase of a male canine's ejaculation occurs during the  copulatory tie , and contains mostly prostatic fluid. [ 57 ]


The  ejaculatory ducts  ( ductus ejaculatorii ) are paired structures in the  male reproductive system . [ 1 ]  Each ejaculatory duct is formed by the union of the  vas deferens  with the  duct of the seminal vesicle . [ 2 ]  They pass through the  prostate , and open into the  urethra  above the  seminal colliculus . During  ejaculation ,  semen  passes through the prostate gland, enters the urethra and exits the body via the  urinary meatus . [ 3 ]


Ejaculation occurs in two stages, the emission stage and the expulsion stage. [ 4 ]  The emission stage involves the workings of several structures of the ejaculatory duct; contractions of the prostate gland, the  seminal vesicles , the  bulbourethral gland  and the  vas deferens  push fluids into the  prostatic urethra . [ 3 ]  The semen is stored here until ejaculation occurs. Muscles at the base of the penis contract in order to propel the seminal fluid trapped in the prostatic urethra through the penile urethra and expel it through the  urinary meatus .  The ejaculate is expelled in spurts, due to the movement of the muscles propelling it. These muscle contractions are related to the sensations of orgasm for the male. [ 5 ]


Sperm  are produced in the testes and enter the ejaculatory ducts via the vas deferens. As they pass by the seminal vesicles, a fluid rich in fructose combines with the sperm. This addition nourishes the sperm in order to keep them active and motile. [ 6 ]  Seminal fluid continues down the ejaculatory duct into the prostate gland, where an alkaline prostatic fluid is added. [ 4 ]  This addition provides the texture and odor associated with semen. [ 4 ]  The alkalinity of the prostatic fluid serves to neutralize the acidity of the female vaginal tract in order to prolong the survival of sperm in this harsh environment. [ 6 ]  Semen is now a fructose-rich, alkaline fluid containing sperm as it enters the bulbourethral glands below the prostate. [ 6 ]  The bulbourethral glands secrete a small amount of clear fluid into the urethra before the ejaculate is expelled. The functions of this fluid are not entirely known but are suggested to aid in lubricating the male urethra in preparation for the semen during ejaculation. [ 4 ]  The amount of semen produced and expelled during ejaculation corresponds to the length of time that the male is sexually aroused before ejaculation occurs. [ 4 ]  Generally, the longer the period of arousal, the larger the amount of seminal fluid. [ 7 ]


Ejaculation and  orgasm  may occur simultaneously, however they are not coupled, in that one may occur without the other. For example, a man may have a dry orgasm (termed  retrograde ejaculation [ 8 ] ); there is no expulsion of ejaculate however the man still experiences orgasm. [ 4 ]  Also, paraplegics may ejaculate seminal fluid but not experience the sensation of orgasm. [ 4 ]


Ejaculatory duct obstruction  is an acquired or congenital pathological condition in which one or both ejaculatory ducts are obstructed. [ 9 ]  In the case that both ejaculatory ducts are obstructed, this illness presents with the symptoms of  aspermia  and male  infertility . [ 9 ] [ 10 ]


Surgery to correct  benign prostatic hyperplasia  may destroy these ducts resulting in  retrograde ejaculation . Retrograde ejaculation empties the seminal fluid formed in the emission phase into the bladder of the male instead of expelling it through the urethra and out the tip of the penis. [ 4 ]  This results in a dry orgasm, where orgasm may still be experienced but without expulsion of semen from the ejaculatory ducts.


Electroejaculation  is a procedure used to  obtain semen samples  from sexually mature  male mammals . The procedure is used for breeding programs and research purposes in various species, as well as in the treatment of  ejaculatory dysfunction  in human males. This procedure is used frequently with large mammals, particularly  bulls  and some domestic animals, as well as humans who have certain types of  anejaculation .  Electroejaculation has also been used for the  cryoconservation of animal genetic resources , where semen is stored in low temperatures with the intent of conserving genetic material and future revival.


In the practice of  veterinary medicine  and  animal science , it is common to collect semen from domestic  ruminants  using electro-ejaculation without [ why? ]  sedation or anesthesia. Only in  goats  is mild sedation sometimes used. Because of the significant skeletal muscle contractions it causes, electroejaculation is not used in  stallions  — except in rare cases, under general anesthesia. [ citation needed ]


In humans, electroejaculation is usually carried out under a  general anesthetic . [ 1 ]  An electric probe is inserted into the  rectum  adjacent to the  prostate gland . The probe delivers an AC voltage, usually 12–24 volts sine wave at a frequency of 60 Hz, with a current limited to usually 500 mA, although some devices can generate currents of up to 1 A. The probe is activated for 1–2 seconds, referred to as a stimulus cycle. Ejaculation usually occurs after 2–3 stimulus cycles. Care must be taken when using currents greater than 500 mA, as tissue burns may result due to heating of the probe. [ 2 ]  The electric current stimulates nearby nerves, resulting in contraction of the  pelvic muscles  and  ejaculation .


The procedure has been adopted and modified as an assisted reproduction technique for managing endangered species, to ensure the production of offspring from incompatible pairs of animals where artificial insemination is feasible. [ 5 ]


Electroejaculation may also be used for  posthumous sperm retrieval  in brain-dead humans. [ 6 ]