Depending on thespecies, spermatozoa can fertilize ova externally or internally. Inexternal fertilization, the spermatozoa fertilize the ova directly, outside of the female's sexual organs. Femalefish, for example,spawn ova into their aquatic environment, where they are fertilized by the semen of the male fish.
During the process ofejaculation, sperm passes through theejaculatory ducts and mixes with fluids from theseminal vesicles, theprostate, and thebulbourethral glands to form the semen. The seminal vesicles produce a yellowish viscous fluid rich in fructose and other substances that makes up about 70% of human semen.[5] The prostatic secretion, influenced by dihydrotestosterone[citation needed], is a whitish (sometimes clear), thin fluid containing proteolytic enzymes, citric acid, acid phosphatase and lipids.[5] The bulbourethral glands secrete a clear secretion into the lumen of theurethra to lubricate it.[6]
Sertoli cells, which nurture and support developingspermatocytes, secrete a fluid into seminiferous tubules that helps transport sperm to the genital ducts. The ductuli efferentes possess cuboidal cells withmicrovilli andlysosomal granules that modify the ductal fluid by reabsorbing some fluid. Once the semen enters the ductus epididymis the principal cells, which containpinocytotic vessels indicating fluid reabsorption, secrete glycerophosphocholine which most likely inhibits prematurecapacitation. The accessory genital ducts, theseminal vesicle,prostate glands, and thebulbourethral glands, produce most of the seminal fluid.
Seminal plasma of humans contains a complex range oforganic andinorganic constituents.
The seminal plasma provides a nutritive and protective medium for the spermatozoa during their journey through the female reproductive tract. The normal environment of thevagina is a hostile one (cf.sexual conflict) forsperm cells, as it is veryacidic (from the native microflora producinglactic acid), viscous, and patrolled by immune cells. The components in the seminal plasma attempt to compensate for this hostile environment. Basicamines such asputrescine,spermine,spermidine andcadaverine are responsible for the smell and flavor of semen. These alkaline bases counteract and buffer the acidic environment of the vaginal canal, and protectDNA inside thesperm from acidic denaturation.
The components and contributions of semen are as follows:
Approximately 200 million to 500 million spermatozoa (also calledsperm orspermatozoans), produced in thetestes, are released per ejaculation. If a man has undergone avasectomy, he will have no sperm in the ejaculate.
Galactose,mucus (serve to increase the mobility of sperm cells in the vagina and cervix by creating a less viscous channel for the sperm cells to swim through, and preventing their diffusion out of the semen. Contributes to the cohesive jelly-like texture of semen),pre-ejaculate,sialic acid.
A 1992World Health Organization report described normal human semen as having a volume of 2 mL or greater,pH of 7.2 to 8.0, sperm concentration of 20×106 spermatozoa/mL or more, sperm count of 40×106 spermatozoa per ejaculate or more, and motility of 50% or more with forward progression (categories a and b) of 25% or more with rapid progression (category a) within 60 minutes of ejaculation.[9]
A 2005 review of the literature found that the average reported physical and chemical properties of human semen were as follows:[10]
Semen is typically translucent with white, grey or even yellowish tint, with a viscous consistency similar to that ofegg whites. Blood in the semen can cause a pink or reddish colour, known ashematospermia, and may indicate a medical problem which should be evaluated by a doctor if the symptom persists.[11]
After ejaculation, the latter part of the ejaculated semencoagulates immediately,[12] forming globules,[13] while the earlier part of the ejaculate typically does not.[14] After a period typically ranging from 15 to 30 minutes,prostate-specific antigen present in the semen causes the decoagulation of the seminal coagulum.[15] It is postulated that the initial clotting helps keep the semen in the vagina,[12] whileliquefaction frees the sperm to make their journey to the ova.[12]
A 2005 review found that the average reported viscosity of human semen in the literature was 3–7centipoises (cP), or, equivalently, millipascal-seconds (mPa·s).[10]
Semen quality is a measure of the ability of semen to accomplish fertilization. Thus, it is a measure of fertility in a man. It is the sperm in the semen that is the fertile component, and therefore semen quality involves both sperm quantity and sperm quality.[16]
Quantity
The volume of semen ejaculate varies but is generally about 1 teaspoonful or less. A review of 30 studies concluded that the average was around 3.4 milliliters (mL), with some studies finding amounts as high as 5.0 mL or as low as 2.3 mL.[10] In a study with Swedish and Danish men, a prolonged interval betweenejaculations caused an increase in the sperm count in the semen but not an increase in the semen volume.[17]
Storage
Semen can be stored in diluents such as theIllini Variable Temperature (IVT) diluent, which have been reported to be able to preserve high fertility of semen for over seven days.[18] The IVT diluent is composed of several salts, sugars and antibacterial agents and gassed withCO2.[18]
Semen cryopreservation can be used for far longer storage durations. For human sperm, the longest reported successful storage with this method is 21 years.[19]
The presence of blood in semen orhematospermia may be undetectable (it can only be seen microscopically) or visible in the fluid. Its cause could be the result ofinflammation,infection, blockage, or injury of the male reproductive tract or a problem within theurethra,testicles,epididymis orprostate. It usually clears up without treatment, or withantibiotics, but if persistent furthersemen analysis and otherurogenital system tests might be needed to find out the cause.
Allergy
In rare circumstances, humans can develop an allergy to semen, called human seminal plasma sensitivity. It appears as a typical localized or systemicallergic response upon contact with seminal fluid. There is no one protein in semen responsible for the reaction. Symptoms can appear after first intercourse or after subsequent intercourse. A semen allergy can be distinguished from a latex allergy by determining if the symptoms disappear with use of acondom. Desensitization treatments are often very successful.[27][28]
Benefits to females
Among numerous species in the animal kingdom, females may benefit from absorbing nutrients and proteins from seminal fluid for food, antiviral and antibacterial properties, and enhanced fertilisation. In humans, seminal fluid provides anti-viral activity towardsherpes simplex virus and can transfer anti-microbial peptidescathelicidin andlactoferrin. In birds and mammals, mutualistic bacteria such asLactobacillus have been detected in fluid transferral.[20]
A study on the effect of semen in male-to-female transmission ofHIV, in both humans and non-human primates (rhesus macaques), noted that regular intravaginal exposure to a healthy male's semen modulates the microenvironment in thefemale reproductive tract (FRT), and, paradoxically, improves the resistance in females against acquiring HIV by activating their bodies anti-HIV mechanisms.[29]
Society and culture
Qigong
Qigong andChinese medicine place huge emphasis on a form of energy called 精 (pinyin: jīng, also a morpheme denoting "essence" or "spirit")[30][31] – which one attempts to develop and accumulate. "Jing" is sexual energy and is considered to dissipate with ejaculation, somasturbation is considered "energy suicide" amongst those who practice this art. According to Qigong theory, energy from many pathways/meridians becomes diverted and transfers itself to the sexual organs during sexual excitement. The ensuing orgasm and ejaculation will then finally expel the energy from the system completely. The Chinese proverb 一滴精，十滴血 (pinyin: yì dī jīng, shí dī xuè, literally: a drop of semen is equal to ten drops of blood) illustrates this point.
The scientific term for semen in Chinese is 精液 (pinyin: jīng yè, literally: fluid of essence/jing) and the term forsperm is 精子 (pinyin: jīng zǐ, literally: basic element of essence/jing), two modern terms with classical referents.
Indian philosophy
TheUpanishads, principal scriptures ofHinduism, propound a creation theory wherein thesupreme self transmutes itself to become the creation by exerting tremendous effort and strenuous labor (śrama), which is enabled on bytapas or "heat", considered as the most important element in the entire creation process.[32] The wordtapas, insanskrit literature, is understood as a reference to the sexual heat or warmth that incubates the birth oflife.[33] The root wordtapas was commonly used for descriptions of sexual desire and love.[34] The wordkama (desire) was homologized withtapas (heat) to explain the emotions and energy that leads tointercourse.[35][36]
The connection betweenbodily heat (tapas) and sexual desire (kama) is not just metaphorical but is found to be rooted inphysiology, "All adolescent and fertile adults are hot."[37]: 126 The internal bodily heat, apart from being present inherently in certain body types (thinness more heat), is generated by processes such as "menstruation,childbirth, consumption of hot food, sexual desire" and certainemotions like anger and jealousy.[37]: 126 While heat is regarded as necessary to sustain life, with complete coldness corresponding to death, excessive bodily heat is "undesirable and dangerous" as it causes the body to deteriorate by internal consumption. A state of "relative coolness" is considered ideal.[37]: 126
Women, in general, are deemed as relatively hotter than men, partly due to menstruation and pregnancies, which result in higher concentrations of blood to the womb. Menstruation, in particular is considered as extremely heating, a process likened to "boiling over" and is sought to be alleviated by acts such asmenstrual seclusion, and oiling-bathing of the menstruating women, apart from rituals.[37]: 126 In the Indian state ofKerala, a ritual conducted for virgin girls wastalikettukalyanam, in which the girls are wedded to a boy or a man in a mock-marriage and after consummating are separated without any claims on each other.[37]: 127 In sexually matured females, menstruation and unfulfilled sexual desire is believed to boil over their blood, with theheat making them violent and maniacal unless they are regularly cooled down by man's semen, which, is considered to be an extremely cooling substance.[37]: 127 Though excessive heat in a woman is synonymous with "shakti and latent fertility", it is potentially dangerous and must be restrained, lessened and transmuted. This is sought to be achieved by "binding", wherein women wear tight upper clothing, bangles and necklaces; and "sealing the body" in oil baths and herbal powders; and through regular sexual intercourse. A woman is said to be really cool only after childbirth and had breast-feed her baby.[37]: 126
Men, too, overheat in absence of regular ejaculation and can become a danger.[37]: 127 In men, the semen heats up gradually and, if not ejaculated, should be channelled through thekundalini by means of demanding yogic practices.[37]: 127 Hindu men have an ascetic–erotic conundrum as they believe abstinence yields power, as well as in satisfying their desires as a necessity.[37]: 115 Morris Carstairs, in a report on culture and personality study, stated that Indian men who are seemingly healthy are preoccupied with real or imaginedspermatorrhea, with the belief that semen is not easily formed and "it takes 40 days, and 40 drops of blood, to make one drop of semen". He observed that when sexual behaviours are restricted, sexualincontinence follows with resultant guilt.[37]: 115 In females, the corresponding fear of loss of sexual fluids is found in anxieties overvaginal discharge (sravam), which is believed to be a cooling body lubricant but whose loss leaves them "overheated anddisarticulated, in a state of disease."[37]: 117–118 Anxiety about loss of sexual fluids is caused from a misdiagnosis ofsexual guilt, instead of correcting the psyche of a person the focus is shifted onto the substance (semen, sravam), resulting in subsequentpathologization.: 115 [37]
InAyurveda, the term generally used for both male semen and femaleegg cell isShukra. People with healthy shukra appear stronger and confident, with eyes and skin that seem lustrous. Those who lack higher shukra appear exhausted and lackluster, while also struggling in creative endeavours. Drinking lots of Water and proper digestion of highly nourishing foods (milk, ghee, nuts) yield healthy shukra.[38]Charaka statesbrahmacharya (abstinence), proper diet, and rest/sleep as the three pillars of life. Indulgence in sexual activity is healthy for stronger individuals, but in weaker people it weakens them further, and is sought to be alleviated by abstinence as it restores shukra, which is always produced as a result of the digestion of food one eats.[38] Ayurveda makes no preference for a celibate or monastic lifestyle, nor does it stress on morality being a part ofhuman sexuality. The health of an individual's shukra and theirdharma decides the degree of their sexual activity; for a householder sexual expression is common, while it is not so for a renunciate monk.[38]
Greek philosophy
InAncient Greece,Aristotle remarked on the importance of semen: "For Aristotle, semen is the residue derived from nourishment, that is of blood, that has been highly concocted to the optimum temperature and substance. This can only be emitted by the male as only the male, by nature of his very being, has the requisite heat to concoct blood into semen."[39] According to Aristotle, there is a direct connection between food and semen: "Sperms are the excretion of our food, or to put it more clearly, as the most perfect component of our food."[40]
The connection between food and physical growth, on the one hand, and semen, on the other, allows Aristotle to warn against "engag[ing] in sexual activity at too early an age ... [since] this will affect the growth of their bodies. Nourishment that would otherwise make the body grow is diverted to the production of semen. Aristotle is saying that at this stage thebody is still growing; it is best for sexual activity to begin when its growth is 'no longer abundant', for when the body is more or less at full height, the transformation of nourishment into semen does not drain the body of needed material."[41]
Additionally, "Aristotle tells us that the region round the eyes was the region of the head most fruitful of seed ("most seedy" σπερματικώτατος), pointing to generally recognised effects upon the eyes of sexual indulgence and to practices which imply that seed comes from liquid in the region of the eyes."[42] This may be explained by the belief of thePythagoreans that "semen is a drop of the brain [τὸ δε σπέρμα εἶναι σταγόνα ἐγκέφαλου]."[43]
GreekStoic philosophy conceived of theLogos spermatikos ("seminal word") as the principle of active reason that fecundated passivematter.[44] The Jewish philosopherPhilo similarly spoke in sexual terms of the Logos as the masculine principle of reason that sowed seeds of virtue in the feminine soul.[45]
The Christian PlatonistClement of Alexandria likened the Logos to physical blood[46] as the "substance of the soul",[47] and noted that some held "that the animal semen is substantially foam of its blood".[48] Clement reflected an early Christian view that "the seed ought not be wasted nor scattered thoughtlessly nor sown in a way it cannot grow."[49]
Women were believed to have their own version, which was stored in the womb and released during climax. Retention was believed to causefemale hysteria.[50]
In somepre-industrial societies, semen and other body fluids were revered because they were believed to be magical.Blood is an example of such a fluid, but semen was also widely believed to be of supernatural origin and effect and was, as a result, considered holy or sacred. The ancientSumerians believed that semen was "a divine substance, endowed on humanity byEnki", the god of water.[52]: 28 [53] The semen of a god was believed to have magical generative powers.[52]: 49 InSumerian mythology, when Enki's seed was planted in the ground, it caused the spontaneous growth of eight previously nonexistent plants.[52]: 49 [54] Enki was believed to have created theTigris andEuphrates rivers by masturbating and ejaculating into their emptyriverbeds.[52]: 32, 49 The Sumerians believed that rain was the semen of the sky-godAn,[55] which fell from the heavens to inseminate his consort, the earth-goddessKi,[55] causing her to give birth to all the plants of the earth.[55]
Theorchid's twin bulbs were thought to resemble thetesticles, which is the etymology of the diseaseorchiditis. There was an ancient Roman belief that the flower sprang from the spilled semen of copulatingsatyrs.[56]
In a number of mythologies around the world, semen is often considered analogous tobreast milk. In the traditions of Bali, it is considered to be the returning or refunding of the milk of the mother in an alimentary metaphor. The wife feeds her husband who returns to her his semen, the milk of human kindness.[57]
Nancy Friday's book,Men in Love – Men's Sexual Fantasies: The Triumph of Love over Rage (1982), suggests that swallowing semen is high on a man's intimacy scale.[58]
Espionage
Semen stain on carpet observed with and without ultraviolet light
TheBorborites, also known as the Phibionites, were an early ChristianGnostic sect during the late fourth century AD whose alleged practices involving sacred semen are described by the early Christian heretic-hunterEpiphanius of Salamis in hisPanarion.[60][61][62][63] Epiphanius claims that the Borborites had a sacred text called theGreater Questions of Mary, which contained an episode in which, during a post-resurrection appearance,Jesus tookMary Magdalene to the top of a mountain, where he pulled a woman out of his side and engaged in sexual intercourse with her.[61][60][63] Then, uponejaculating, Jesus drank his own semen and told Mary, "Thus we must do, that we may live."[61][60][63] Upon hearing this, Mary instantly fainted, to which Jesus responded by helping her up and telling her, "O thou of little faith, wherefore didst thou doubt?"[61][63] This story was supposedly the basis for the BorboriteEucharist ritual, in which they allegedly engaged in orgies and drank semen and menstrual blood as the "body and blood of Christ" respectively.[60][63][61]Bart D. Ehrman, a scholar of early Christianity, casts doubt on the accuracy of Epiphanius's summary, commenting that "the details of Epiphanius's description sound very much like what you can find in the ancient rumor mill about secret societies in the ancient world".[60]
In some cultures, semen is considered to have special properties associated withmasculinity. Several tribes ofPapua New Guinea, including theSambia and theEtoro, believe that semen promotes sexual maturation among the younger men of their tribe. To them, semen possesses the manly nature of the tribal elders, and in order to pass down their authority and powers, younger men of their next generation mustfellate their elders and ingest their semen. Prepubescent and postpubescent males are required to engage in this practice.[64][65] This act may also be associated with the culturally active homosexuality throughout these and other tribes.[66]
Semen ingestion has had central importance in some cultures around the world. InBaruya culture, there is a secret ritual in which boys givefellatio to young males and drink their semen, to "re-engender themselves before marriage".[67]
Sexual
An illustration ofgokkunAn Illustration of snowballing
There are several sexual practices involving the ingestion of semen, which may be done with one or more partners. Practices involving the oral intake of semen include:
Felching is asexual practice involving the act of sucking semen out of theanus of one's partner. According to the entry for "felch" in theOxford English Dictionary, the earliest occurrence of the word in print appears to have been inThe Argot of the Homosexual Subculture by Ronald A. Farrell in 1972, although this usage was as a synonym foranilingus.[68]
Gokkun (ごっくん) is aJapanese term for sexual activity in which a person, usually a woman, consumes the semen of one or more men, often from some kind of container.[69] "Gokkun" can also refer to the sexual act of swallowing semen after performing fellatio or participating in abukkake.[69][70] The word "gokkun" isonomatopoetic, and translates roughly as the English word "gulp", the sound made by swallowing.[71]
Cum swapping /snowballing /snowdropping is the sexual practice in which one person takes someone's semen into their mouth and then passes it to the mouth of the person who ejaculated the semen, usually throughkissing.[72][73][74][75][76][77] The term was originally used only bygay andbisexual men.[73] Researchers who surveyed over 1,200 gay or bisexual men at New YorkLGBT community events in 2004 found that around 20% said they had engaged in snowballing at least once.[78]
Slang terms for semen includecum,jism (also shortened tojizz),spunk (primarilyBritish English),spooge and/orsplooge,load,nut,seed, andlove juice.[79][80] The termcum can also refer to anorgasm (when used as a verb rather than as a noun), whileload is derived from the phraseblowing a load, referring to an ejaculation. The termnut originally referred to atesticle, but can be used to refer to both semen and ejaculation.
^Baker, R (1993). "Human sperm competition: Ejaculate adjustment by males and the function of masturbation".Animal Behaviour.46 (5): 861.doi:10.1006/anbe.1993.1271.S2CID53201940.
^Balk, S. P.; Ko, YJ; Bubley, GJ (2003). "Biology of Prostate-Specific Antigen".Journal of Clinical Oncology.21 (2):383–91.doi:10.1200/JCO.2003.02.083.PMID12525533.
^Bonde, J. P.; Ernst, E.; Jensen, T. K.; Hjollund, N. H.; Kolstad, H.; Henriksen, T. B.; Scheike, T.; Giwercman, A.; Olsen, J.; Skakkebaek, N. E. (1998-10-10). "Relation between semen quality and fertility: a population-based study of 430 first-pregnancy planners".Lancet.352 (9135):1172–1177.doi:10.1016/S0140-6736(97)10514-1.ISSN0140-6736.PMID9777833.S2CID24217414.
^abWatson, PF (1993). "The potential impact of sperm encapsulation technology on the importance of timing of artificial insemination: A perspective in the light of published work".Reproduction, Fertility and Development.5 (6):691–9.doi:10.1071/RD9930691.PMID9627729.
^Sublett, J. Wesley; Bernstein, Jonathan A. (2011). "Seminal Plasma Hypersensitivity Reactions: An Updated Review".Mount Sinai Journal of Medicine.78 (5):803–809.doi:10.1002/msj.20283.PMID21913207.
^Tripolitis, Antonia (2002).Religions of the Hellenistic-Roman Age. Wm. B. Eerdmans Publishing. pp. 37–38.ISBN0-8028-4913-X.
^"And when she (intelligence) lives as a comely wife with comely Reason (Logos), that is with virtuous Reason, this self-same Reason himself undertakes the care of her, sowing, like a husband, the most excellent concepts in her." Philo,De Spec. Leg., § 7.Mead, G.R.S (1906)."Philo of Alexandria and the Hellenistic Theology".Thrice Greatest Hermes: Studies in Hellenistic Theosophy and Gnosis. Vol. I. London and Benares: The Theosophical Publishing Society. p. 222.ISBN0-87728-947-6.Archived from the original on 2010-12-04. Retrieved2010-01-17.{{cite book}}:ISBN / Date incompatibility (help)
^Farrell, Ronald A. (March 1972). "The Argot of the Homosexual Subculture".Anthropological Linguistics.14 (3). The Trustees of Indiana University:97–109.ISSN0003-5483.JSTOR30029496.
^Marx, Eve (2004). "Answers to It's all how you say it: sexual slang".What's Your Sexual IQ?. New York: Citadel Press. p. 90.ISBN0-8065-2610-6.Archived from the original on November 15, 2021. RetrievedDecember 7, 2008.
Grizard, G; Sion, B; Bauchart, D; Boucher, D (31 March 2000). "Separation and quantification of cholesterol and major phospholipid classes in human semen by high-performance liquid chromatography and light-scattering detection".Journal of Chromatography B: Biomedical Sciences and Applications.740 (1):101–7.doi:10.1016/S0378-4347(00)00039-6.PMID10798299.
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