Editing Female ejaculation (section)

==Research==
===General===
[[File:Vulva with vaginal fluid (ejaculation - squirting).png|thumb|Vaginal fluids after ejaculation.]]

There have been few studies on female ejaculation.<ref name="Estupinyà"/> Much of the problem in arriving at a consensus relates to a failure to adopt generally agreed-on definitions<ref name="Taverner"/><ref name="schubach02">{{cite journal |author=Schubach G |title=The G-spot is the female prostate |journal=Am. J. Obstet. Gynecol. |volume=186 |issue=4 |pages=850; author reply 850 |date=April 2002 |pmid=11967519 |doi= 10.1067/mob.2002.121628|doi-access=free }}</ref> or research methodology.<ref name="Taverner"/> Research has used highly selected individuals, case studies, or very small numbers of subjects, making generalization difficult. For instance, much of the research into the nature of the fluid focuses on determining whether it is or contains urine.<ref name="Estupinyà"/><ref name="Taverner"/> Rodriguez et al. stated that "many individuals refer to any fluid expressed from the vagina or urethra during coitus as female ejaculate, which leads to significant confusion in the literature."<ref name="rodriguez"/>

There are also problems involved in the collection of specimens and issues of contamination. Since the area of interest is the para-urethral glands, it is impossible to completely separate the secretions from urine, especially considering that there may be [[retrograde ejaculation]] into the urethra towards the bladder. Research has attempted to use chemicals that are excreted in the urine so that any urinary contamination can be detected. Further methodological issues include the fact that the composition of the fluid appears to vary with the menstrual cycle,<ref>{{cite journal |author=Zaviacic M |title=The fluid of female urethral expulsions analysed by histochemical electron-microscopic and other methods |journal=Histochem. J. |volume=16 |issue=4 |pages=445–7 |date=April 1984 |pmid=6538874 |doi= 10.1007/BF01002874|author2=Jakubovský J |author3=Polák S |display-authors=3 |last4=Zaviačičová |first4=A. |last5=Holomáň |first5=I. K. |last6=Blazekova |first6=J. |last7=Gregor |first7=P.|s2cid=27878970 }}</ref> and that the biochemical profile of the para-urethral tissues varies with age.<ref>{{cite journal |vauthors=Zaviacic M, Porubský J, Vierik J, Holomán IK |title=[Enzymes of the female prostate during the fertile age and after menopause. Comparative histochemical study] |language=sk |journal=Cesk Gynekol |volume=54 |issue=10 |pages=755–60 |date=December 1989 |pmid=2630042 }}</ref> Other issues relate to the sensitivity and specificity of the markers chosen. The key questions are the source of the fluid produced, and its composition.<ref name="bohlen"/>

Whether the fluid is secreted by the Skene's gland through and around the urethra has also been a topic of discussion; while the exact source and nature of the fluid remain controversial among medical professionals, and are related to doubts over the existence of the [[G-spot]],<ref name="Balon, Segraves"/><ref name="Greenberg"/><ref name="rodriguez"/> there is substantial evidence that the Skene's gland is the source of female ejaculation.<ref name=pastor/><ref name="rodriguez"/> The function of female ejaculation, however, remains unclear.<ref name="rodriguez"/>

===Female ejaculation vs. squirting or gushing ===
Some research has distinguished between female ejaculation and what is colloquially known as squirting or gushing. These terms are used by the public interchangeably, which often leads to confusion. In these research publications, it is suggested that "real" female ejaculation is the release of a very scanty, thick, and whitish fluid from the Skene's gland, while the "squirting" or "gushing" (shown frequently in pornography) is a different phenomenon: the expulsion of clear and abundant fluid, which has been shown to be a diluted fluid from the urinary bladder.<ref name="pastor"/><ref name="Salama"/>

===Relation to urinary incontinence===
Towards the later part of the 20th century, there was significant confusion between female ejaculation and [[coital incontinence]]. In 1982, Bohlen explained the accepted wisdom:<ref name="bohlen">{{cite journal |author=Bohlen JG |title="Female Ejaculation" and urinary stress incontinence |journal=J. Sex Res. |volume=18 |issue=4 |pages=360–8 |year=1982 |doi=10.1080/00224498209551161}}</ref>

{{blockquote|The previously accepted notion that all fluid expelled during a woman's orgasm is urine is now being challenged... sexologists must take care not to assume now that any fluid produced at orgasm is "female ejaculate".}}

Scientific studies from the 1980s and later have demonstrated that the substance produced is distinct from urine, though it does show similarities such as alkalinity with urine.<ref name=Kratochvil>{{cite journal |author = Kratochvíl Stanislav |date=April 1994 | title = Orgasmic expulsions in women | journal = Českoslovenaká Psychiatrie | volume = 90 | issue = 2 | pages = 71–7 | pmid = 8004685 }}</ref> Davidson's study of 1,289 women found that the sensation of ejaculation was very similar to that of urination.<ref name="davidson"/> One study by [[Gary Schubach]] used [[urethral catheterization]] in order to separate urine from orgasmic expulsions from elsewhere in the body. Seven women claiming to have ejaculations expelled large volumes of urine through the catheter at orgasm, and little to no other fluid.<ref name=Schubach>{{cite journal |author = Gary Schubach |date=August 2001| title = Urethral Expulsions During Sensual Arousal and Bladder Catheterization in Seven Human Females | journal = Electronic Journal of Human Sexuality | volume = 4}}</ref>

It may be important for physicians to establish whether there is in fact any incontinence in women who report ejaculation, to avoid unnecessary interventions.<ref name=Pastor2013/><ref name="pmid19170835"/> It is also important for physicians to distinguish orgasmic ejaculation from vaginal discharges which may require further investigation and treatment. In individual cases, the exact source of any reported discharge may not be obvious without further investigation.<ref name="pmid15166070">{{cite journal| author=Mitchell H| title=Vaginal discharge--causes, diagnosis, and treatment. | journal=BMJ | year= 2004 | volume= 328 | issue= 7451 | pages= 1306–8 | pmid=15166070 | doi=10.1136/bmj.328.7451.1306 | pmc=420177 }}</ref>

===Nature of different fluids===
Critics have maintained that ejaculation is either [[stress incontinence]] or [[vaginal lubrication]].<ref name="rodriguez"/> Research in this area has concentrated almost exclusively on attempts to prove that the ejaculate is not urine,<ref name="chalker02"/><ref>{{cite journal |author=Belzer EG |title=A review of female ejaculation and the Grafenberg spot |journal=Women Health |volume=9 |issue=1 |pages=5–16 |year=1984 |pmid=6367229 |doi= 10.1300/J013v09n01_02}}</ref> measuring substances such as [[urea]], [[creatinine]], [[prostatic acid phosphatase]] (PAP), [[prostate-specific antigen]] (PSA),<ref name="zaviacic99">{{cite web|url=http://www.doctorg.com/sexual_products/ebook_female_prostate.html |title=Zaviacic M. The human female prostate: From Vestigial Skene's Paraurethral Glands and Ducts to Woman's Functional Prostate. Slovak Academic Press, Bratislava 1999 |publisher=Doctorg.com |access-date=2011-10-30 |url-status=dead |archive-url=https://web.archive.org/web/20111028082511/http://www.doctorg.com/sexual_products/ebook_female_prostate.html |archive-date=2011-10-28 }}</ref> [[glucose]] and [[fructose]]<ref>{{cite journal |vauthors=Zaviačič M, Doležalová S, Holomáň IK, Zaviačičová A, Mikulecký M, Valer Brázdil V |title=Concentrations of Fructose in Female Ejaculate and Urine: A Comparative Biochemical Study |journal=J. Sex Res. |volume=24 |issue= 1|pages=319–25 |year=1988 |doi=10.1080/00224498809551431|pmid=22375668 }}</ref> levels. Early work was contradictory; the initial study on one woman by Addiego and colleagues, reported in 1981,<ref name="addiego"/> could not be confirmed in a subsequent study on 11 women in 1983,<ref name=goldberg>{{cite journal |author1=Goldberg, DC |author2=Whipple, B |author3=Fishkin, RE |author4=Waxman H |author5=Fink PJ |author6=Wiesberg M | year = 1983 | title = The Grafenberg Spot and female ejaculation: a review of initial hypotheses | journal = J Sex Marital Ther | volume = 9 | issue = 1 | pages = 27–37 | pmid =6686614 | doi = 10.1080/00926238308405831 }}</ref> but was confirmed in another 7 women in 1984.<ref name="belzerjsr84"/> In 1985, a different group studied 27 women and found only urine,<ref name=alzate85>{{cite journal |author=Alzate H |title=Vaginal eroticism: a replication study |journal=Arch Sex Behav |volume=14 |issue=6 |pages=529–37 |date=December 1985 |pmid=4084052 |doi= 10.1007/BF01541753|s2cid=44699346 }}</ref> suggesting that results depend critically on the methods used.{{citation needed|date=May 2012}}

A 2007 study on two women involved [[ultrasound]], [[endoscopy]], and biochemical analysis of fluid. The ejaculate was compared to pre-orgasmic urine from the same woman, and also to published data on [[male ejaculation|male ejaculate]]. In both women, higher levels of PSA, PAP, and glucose but lower levels of [[creatinine]] were found in the ejaculate than the urine. PSA levels were comparable to those in males.<ref name="wimpissinger">{{cite journal |vauthors=Wimpissinger F, Stifter K, Grin W, Stackl W |title=The female prostate revisited: perineal ultrasound and biochemical studies of female ejaculate |journal=J Sex Med |volume=4 |issue=5 |pages=1388–93; discussion 1393 |date=September 2007 |pmid=17634056 |doi=10.1111/j.1743-6109.2007.00542.x }}</ref>

Ultrasounds from a 2014 study, involving seven women who reported recurring massive fluid emission during sexual arousal, confirmed thorough bladder emptiness before stimulation, noticeable bladder filling before squirting and demonstrated that the bladder had again been emptied after squirting. Although small amounts of prostatic secretions are present in the emitted fluid, the study suggests that squirting is essentially the involuntary emission of urine during sexual activity.<ref name="Salama"/>

===Source of fluid===
One very practical objection relates to the reported volumes ejaculated, since this fluid must be stored somewhere in the pelvis, of which the [[urinary bladder]] is the largest source. The actual volume of the para-urethral tissue is quite small. By comparison, male ejaculate varies from {{convert|0.2|-|6.6|ml|USoz|2|abbr=on}} (95% [[confidence interval]]), with a maximum of {{convert|13|ml|USoz|2|abbr=on}}.<ref>{{cite journal |author=MacLeod J |title=Semen quality in 1000 men of known fertility and in 800 cases of infertile marriage |journal=Fertil. Steril. |volume=2 |issue=2 |pages=115–39 |year=1951 |pmid=14823049 |doi= 10.1016/s0015-0282(16)30482-4|doi-access= }}</ref> Therefore, claims of larger amounts of ejaculate are likely to contain at least some amount of urine. The eleven specimens analyzed by Goldberg in 1983,<ref name=goldberg /> ranged from {{convert|3|-|15|ml|USoz|1|abbr=on}}.<ref name="belzerjsr84"/> One source states that Skene's glands are capable of excreting {{convert|30|-|50|ml|USoz|0|abbr=on}} in 30–50 seconds,<ref name=heath/> but it is unclear how this was measured and has not been confirmed. One approach is to use a chemical like [[methylene blue]] so that any urinary component can be detected.<ref name="belzerjsr84">{{cite journal |vauthors=Belzer EG, Whipple W, Moger W |title=On female ejaculation |journal=J. Sex Res. |volume=20 |issue=4 |pages=403–6 |year=1984 |doi=10.1080/00224498409551236}}</ref> Belzer showed that in one woman he studied, the dye was found in her urine, but not her orgasmic expulsion.<ref name="belzer"/>

PAP and PSA have been identified in the para-urethral tissues, using biochemical and immunohistochemical methods, suggesting that the ejaculate is likely to arise from the ducts in these tissues, in a manner homologous to that in the male.<ref>{{cite journal |author1=Pollen, JJ |author2=Dreilinger, A |date=March 1984 | title = Immunohistochemical identification of prostatic acid phosphatase and prostate specific antigen in female periurethral glands | journal = Urology | volume = 23 | issue = 3 | pages = 303–4 | pmid = 6199882 | doi = 10.1016/S0090-4295(84)90053-0}}</ref><ref>{{cite journal |author1=Tepper, SL |author2=Jagirdar, J |author3=Heath, D |author4=Geller, SA |date=May 1984 | title = Homology between the female paraurethral (Skene's) glands and the prostate. Immunohistochemical demonstration | journal = Arch Pathol Lab Med | volume = 108 | issue = 5 | pages = 423–5 | pmid = 6546868 }}</ref><ref>{{cite journal |author1=Zaviacic, Z |author2=Ruzicková, M |author3=Jakubovský, J |author4=Danihel, L |author5=Babál, P |author6=Blazeková, J |date=November 1994 | title = The significance of prostate markers in the orthology of the female prostate | journal = Bratisl Lek Listy | volume = 95 | issue = 11 | pages = 491–7 | pmid = 7533639 }}</ref><ref>{{cite journal |author1=Wernert, N |author2=Albrech, M |author3=Sesterhenn, I |author4=Goebbels, R |author5=Bonkhoff, H |author6=Seitz, G |author7=Inniger, R |author8=Remberger, K | year = 1992 | title = The 'female prostate': location, morphology, immunohistochemical characteristics and significance | journal = Eur Urol | volume = 22 | issue = 1 | pages = 64–9 | pmid = 1385145 |doi=10.1159/000474724 }}</ref><ref>{{cite journal |author1=Zaviacic, Z |author2=Ablin, RJ |date=January 2000 | title = The female prostate and prostate-specific antigen. Immunohistochemical localization, implications of this prostate marker in women and reasons for using the term "prostate" in the human female | journal = Histol Histopathol | volume = 15 | issue = 1 | pages = 131–42 | pmid = 10668204 }}</ref> Another marker common to the prostate/para-urethral tissue in both sexes is [[Uteroglobin|human protein 1]].<ref>{{cite journal |author1=Zaviacic, M |author2=Danihel, L |author3=Ruzicková, M |author4=Blazeková, J |author5=Itoh, Y |author6=Okutani, R |author7=Kawai, T |date=March 1997 | title = Immunohistochemical localization of human protein 1 in the female prostate (Skene's gland) and the male prostate | journal = Histochem J | volume = 29 | issue = 3 | pages = 219–27 | pmid = 9472384 | doi = 10.1023/A:1026401909678|title-link=Skene's gland |s2cid=22166424 }}</ref>

PSA occurs in urine, and is elevated in post-orgasmic samples compared to pre-orgasmic. Simultaneous collection of ejaculate also showed PSA in both urine and ejaculate in all cases, but in higher concentration in the ejaculate than in the urine.<ref name="santamaria">{{cite book | author = Cabello Santamaria, F | year = 1997 | chapter = Female ejaculation: Myths and reality | editor = J.J. Baras-Vass & M.Perez-Conchillo | title = Sexuality and Human Rights: Proceedings of the XIII World Congress of Sexology August 29 | pages = 325–33 | location = Valencia, Spain | publisher = Nau Libres E.C.V.S.A. | chapter-url = http://www.doctorg.com/female-ejaculation-myth-reality-1.htm | access-date = 2008-08-09 | archive-url = https://web.archive.org/web/20080723122603/http://www.doctorg.com/female-ejaculation-myth-reality-1.htm | archive-date = 2008-07-23 | url-status=dead }}</ref> Wimpissinger et al., 2007 reports the PSA level in urine in the 0.16&ndash;0.8 ng/mL range, and in female ejaculate in the 105.9&ndash;213.49 ng/mL range (two participants), more than a hundredfold difference.<ref name="rodriguez"/>