Editing Woman (section)

== Biology ==
[[Image:Anterior view of human female and male, with labels 2.png|upright|thumb|Photograph of an adult female human, with an adult male for comparison. The [[pubic hair]] of both models is removed. |alt=Photograph of an adult female human, with an adult male for comparison. The [[pubic hair]] of both models is removed.]]
{{main|Sex differences in humans}}

Male and female bodies have [[Sex differences in humans|some differences]].  Some differences, such as the external [[sex organs]], are visible, while other differences, such as internal anatomy and genetic characteristics, are not visible.

=== Genetic characteristics ===
{{Main|Sexual differentiation in humans}}
[[Image:Sky spectral karyotype.png|upright|thumb|[[Spectral karyotype]] of a human female|alt=A multi-colored sphere, and a set of chromosomes listed in a data table]]
Typically, the cells of female humans contain two X chromosomes, while the cells of male humans have an X and a Y chromosome.<ref name=Hake>{{cite journal |last1=Hake |first1=Laura |last2=O'Connor |first2=Clare |title=Genetic Mechanisms of Sex Determination |journal=Nature Education |volume=1 |issue=1 |date=2008 |page=25 |url=https://www.nature.com/scitable/topicpage/genetic-mechanisms-of-sex-determination-314/ }}</ref> During [[Human fertilization|early fetal development]], all embryos have phenotypically female genitalia up until week 6 or 7, when a male embryo's gonads differentiate into testes due to the action of the [[SRY gene|''SRY'' gene]] on the Y chromosome.<ref name="Pardue-2001" /> [[Sex differentiation]] proceeds in female humans in a way that is independent of gonadal hormones.<ref name="Pardue-2001">{{cite book |author=Institute of Medicine (US) Committee on Understanding the Biology of Sex and Gender Differences |last2=Wizemann |first2=Theresa M. |last3=Pardue |first3=Mary-Lou |title=Exploring the Biological Contributions to Human Health |chapter=Sex Begins in the Womb |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK222286/ |publisher=National Academies Press (US) |language=en |date= 2001 |isbn=978-0-309-07281-6 |doi=10.17226/10028 |pmid=25057540 |quote=All human individuals{{snd}}whether they have an XX, an XY, or an atypical sex chromosome combination{{snd}}begin development from the same starting point. During early development the gonads of the fetus remain undifferentiated; that is, all fetal genitalia are the same and are phenotypically female. After approximately 6 to 7 weeks of gestation, however, the expression of a gene on the Y chromosome induces changes that result in the development of the testes.}}</ref> Because humans inherit [[mitochondrial DNA]] only from the mother's ovum, [[Genetic genealogy|genealogical]] researchers can trace [[Matrilineality|maternal lineage]] far back in time.

=== Hormonal characteristics, menstruation and menopause ===
{{Main|Menstrual cycle|Menstruation}}
[[Female puberty]] triggers bodily changes that enable [[sexual reproduction]] via [[human fertilization|fertilization]]. In response to chemical signals from the [[pituitary gland]], the [[ovaries]] secrete hormones that stimulate maturation of the body, including increased height and weight, body hair growth, breast development and [[menarche]] (the onset of menstruation).<ref name="UK menarche">{{cite book | last=Hamilton-Fairley | first=Diana | title=Lecture notes. Obstetrics and gynaecology | publisher=Wiley-Blackwell | publication-place=Chichester, UK | date=2009 | isbn=978-1-4051-7801-3 | oclc=230193908}}</ref>

[[File:Pregnancy 26 weeks 1.jpg|thumb|upright|A pregnant woman|alt=nude woman in the middle of pregnancy]]

Most girls go through [[menarche]] between ages 12–13,<ref name="Canadian menarche">{{cite journal|title=Age at menarche in Canada: results from the National Longitudinal Survey of Children & Youth |year= 2010 |pmid=21110899 |doi=10.1186/1471-2458-10-736 |pmc=3001737 |volume=10 |vauthors=Al-Sahab B, Ardern CI, Hamadeh MJ, Tamim H |journal=BMC Public Health |page=736 |doi-access= free }}</ref><ref name="U.S. menarche">{{cite journal |vauthors=Anderson SE, Dallal GE, Must A |title =Relative weight and race influence average age at menarche: results from two nationally representative surveys of US girls studied 25 years apart |journal=Pediatrics |volume=111 |issue=4 Pt 1 |pages=844–850 |date=April 2003 |pmid=12671122 |doi=10.1542/peds.111.4.844}}</ref> and are then capable of becoming [[pregnant]] and [[childbirth|bearing children]]. Pregnancy generally requires [[Insemination|internal fertilization]] of the eggs with [[Spermatozoon|sperm]], via either [[sexual intercourse]] or [[artificial insemination]], though [[in vitro fertilization]] allows fertilization to occur outside the human body.<ref>{{cite web|date=November 14, 2014|title=What is Assisted Reproductive Technology? {{!}} Reproductive Health |url=https://www.cdc.gov/art/whatis.html|url-status=live|archive-url=https://web.archive.org/web/20171101183209/https://www.cdc.gov/art/whatis.html|archive-date=November 1, 2017|publisher=CDC}}</ref> Humans are similar to other large mammals in that they usually give birth to a single offspring per pregnancy, but are unusual in being [[Precociality and altriciality|altricial]] compared to most other large mammals, meaning young are [[Child development|undeveloped]] at time of birth and require the aid of their parents or guardians to fully mature.<ref>{{cite web |title=Overview of Multiple Pregnancy |url=https://www.stanfordchildrens.org/en/topic/default?id=overview-of-multiple-pregnancy-85-P08019 |website=Stanford Medicine Children’s Health }}</ref> Sometimes humans have [[multiple birth]]s, most commonly [[twin]]s.<ref>{{Cite web |title=Twins, Triplets, Multiple Births |url=https://medlineplus.gov/twinstripletsmultiplebirths.html |access-date=2022-07-25 |website=medlineplus.gov}}</ref>

Usually between ages 49–52, a woman reaches [[menopause]], the time when menstrual periods stop permanently, and they are no longer able to bear children.<ref name="NIH2013Def">{{cite web|date=2013-06-28|title=Menopause: Overview|url=http://www.nichd.nih.gov/health/topics/menopause/Pages/default.aspx|url-status=dead|archive-url=https://web.archive.org/web/20150402111845/http://www.nichd.nih.gov/health/topics/menopause/Pages/default.aspx|archive-date=2 April 2015|access-date=8 March 2015|publisher=Eunice Kennedy Shriver National Institute of Child Health and Human Development|df=dmy-all}}</ref><ref name="PubMed2013">{{cite web|date=29 August 2013|title=Menopause: Overview|url=https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072495/|url-status=live|archive-url=https://web.archive.org/web/20170910181404/https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072495/|archive-date=10 September 2017|access-date=8 March 2015|publisher=PubMedHealth|df=dmy-all}}</ref><ref name="Tak2015">{{cite journal|vauthors=Takahashi TA, Johnson KM|date=May 2015|title=Menopause|journal=The Medical Clinics of North America|volume=99|issue=3|pages=521–34|doi=10.1016/j.mcna.2015.01.006|pmid=25841598|doi-access=free}}</ref> Unlike most other mammals, the human lifespan usually extends many years after menopause.<ref>{{Cite journal |last1=Hawkes |first1=K. |last2=O’Connell |first2=J. F. |last3=Jones |first3=N. G. Blurton |last4=Alvarez |first4=H. |last5=Charnov |first5=E. L. |date=1998-02-03 |title=Grandmothering, menopause, and the evolution of human life histories |journal=Proceedings of the National Academy of Sciences |volume=95 |issue=3 |pages=1336–1339 |doi=10.1073/pnas.95.3.1336 |pmc=18762 |pmid=9448332|bibcode=1998PNAS...95.1336H |doi-access=free }}</ref> Many women become [[Grandparent|grandmothers]] and contribute to the care of grandchildren and other family members.<ref>{{Cite web |title=Increasingly Indispensable Grandparents {{!}} YaleGlobal Online |url=https://archive-yaleglobal.yale.edu/content/increasingly-indispensable-grandparents |access-date=2022-07-28 |website=archive-yaleglobal.yale.edu |language=en}}</ref> Many biologists believe that the extended human lifespan is evolutionarily driven by [[kin selection]], though other theories have also been proposed.<ref>{{Cite journal |last1=Kaptijn |first1=Ralf |last2=Thomese |first2=Fleur |last3=van Tilburg |first3=Theo G. |last4=Liefbroer |first4=Aart C. |date=December 2010 |title=How Grandparents Matter: Support for the Cooperative Breeding Hypothesis in a Contemporary Dutch Population |journal=Human Nature |language=en |volume=21 |issue=4 |pages=393–405 |doi=10.1007/s12110-010-9098-9 |pmid=21212819 |pmc=2995872 }}</ref><ref>{{Cite journal |last=Peccei |first=Jocelyn Scott |title=Menopause: Adaptation or epiphenomenon? |journal=Evolutionary Anthropology: Issues, News, and Reviews |date=2001 |volume=10 |issue=2 |pages=43–57 |doi=10.1002/evan.1013 }}</ref><ref>{{Cite journal |last=Kyriazis |first=Marios |title=Ageing Throughout History: The Evolution of Human Lifespan |journal=Journal of Molecular Evolution |date=2020 |language=en |volume=88 |issue=1 |pages=57–65 |doi=10.1007/s00239-019-09896-2 |pmid=31197416 |bibcode=2020JMolE..88...57K }}</ref><ref>{{cite book |doi=10.1002/9781118924396.wbiea2162 |chapter=Grandmother Hypothesis, Grandmother Effect, and Residence Patterns |title=The International Encyclopedia of Anthropology |date=2018 |last1=Blell |first1=Mwenza |pages=1–5 |isbn=978-0-470-65722-5 }}</ref>

=== Morphological and physiological characteristics ===

[[Image:Scheme female reproductive system-en.svg|thumb|upright|The [[human female reproductive system]]|alt=diagram of internal anatomy]]
{{Main|Sex differences in human physiology|Female body shape}}

In terms of [[biology]], the female [[sex organ]]s are involved in the reproductive system, whereas the [[secondary sex characteristic]]s are involved in [[breastfeeding]] children and attracting a mate.<ref name="Buss 2019">{{cite book |doi=10.4324/9780429061417 |title=Evolutionary Psychology |date=2019 |last1=Buss |first1=David M. |isbn=978-0-429-06141-7 |chapter=Evolved Standards of Physical Beauty |pages=283–288 }}</ref> Humans are [[placental mammals]], which means the mother carries the fetus in the uterus and the placenta facilitates the exchange of nutrients and waste between the mother and fetus.<ref>{{Cite web |title=placental mammal {{!}} Characteristics & Facts {{!}} Britannica |url=https://www.britannica.com/animal/placental-mammal |access-date=2022-07-25 |website=www.britannica.com |language=en}}</ref><ref>{{Cite web |title=Placental Mammals |url=https://ucmp.berkeley.edu/mammal/eutheria/placental.html |access-date=2022-07-25 |website=ucmp.berkeley.edu}}</ref>

[[File:Woman breastfeeding an infant.jpg|upright|alt=smiling mother holds baby to breastfeed|left|thumb|A mother [[breastfeeding]] her baby]]

The internal female genitalia consist of the [[ovaries]], gonads that produce female gametes called [[ovum|ova]], the [[fallopian tube]]s, tubular structures that transport the egg cells, the [[uterus]], an organ with tissue to protect and nurture the developing fetus and its [[cervix]] to expel it, the accessory glands ([[Bartholin's gland|Bartholin's]] and [[Skene's gland|Skene's]]), two pairs of glands that help [[vaginal lubrication|lubricate]] during intercourse, and the [[vagina]], an organ used in copulating and birthing. 

The [[vulva]] (external female genitalia)<ref name="Kirkpatrick">{{cite book |doi=10.1007/978-1-4684-3656-3_9 |chapter=The Misnamed Female Sex Organ |title=Women's Sexual Development |date=1980 |last1=Ash |first1=Mildred |pages=171–179 |isbn=978-1-4684-3658-7 }}</ref> consists of the [[clitoris]], [[labia majora]], [[labia minora]] and [[vulval vestibule|vestibule]]. The vestibule is where the vaginal and urethral openings are located. 

The [[mammary gland]]s are hypothesized to have evolved from apocrine-like glands to produce milk, a nutritious secretion that is the most distinctive characteristic of mammals, along with live birth.<ref>{{cite journal |last1=Oftedal |first1=Olav T. |title=The mammary gland and its origin during synapsid evolution |journal=Journal of Mammary Gland Biology and Neoplasia |date=2002 |volume=7 |issue=3 |pages=225–252 |doi=10.1023/a:1022896515287 |pmid=12751889 }}</ref> In mature women, the [[breast]] is generally more prominent than in most other mammals; this prominence, not necessary for milk production, is thought to be at least partially the result of [[sexual selection]].<ref name="Buss 2019" />

[[Estrogens]], which are primary female sex hormones, have a significant impact on a female's body shape. They are produced in both men and women, but their levels are significantly higher in women, especially in those of reproductive age. Besides other functions, estrogens promote the development of female [[secondary sexual characteristic]]s, such as breasts and [[hip]]s.<ref name="pmid9393999">{{cite journal | title = A role for estrogens in the male reproductive system | journal=Nature | volume = 390 | issue = 6659 | pages = 447–448 | year = 1997 | pmid = 9393999 | pmc=5719867 | doi = 10.1038/37352 | last1=Hess | first1=R. A. | last2=Bunick | first2=D | last3=Lee | first3=K. H. | last4=Bahr | first4=J | last5=Taylor | first5=J. A. | last6=Korach | first6=K. S. | last7=Lubahn | first7=D. B. | bibcode=1997Natur.390..509H }}</ref><ref>{{cite journal |last1=Raloff |first1=J |title=Estrogen's Emerging Manly Alter Ego |journal=Science News |date=6 December 1997 |volume=152 |issue=23 |pages=356 |doi=10.2307/3980827 |url=https://www.sciencenews.org/archive/estrogens-emerging-manly-alter-ego |jstor=3980827 }}</ref><ref name="titleScience Blog -- Estrogen Linked To Sperm Count, Male Fertility">{{cite web | url = http://www.scienceblog.com/community/older/1997/B/199701564.html | title = Science Blog – Estrogen Linked To Sperm Count, Male Fertility | access-date = 4 March 2008 | publisher = Science Blog | archive-date = 7 May 2007 | archive-url = https://web.archive.org/web/20070507120938/http://www.scienceblog.com/community/older/1997/B/199701564.html | url-status = dead }}</ref> As a result of estrogens, during [[puberty]], girls develop breasts and their hips widen. Working against estrogen, the presence of [[testosterone]] in a pubescent female inhibits breast development and promotes muscle and facial hair development.<ref name="WebMD">{{cite web | url=http://www.webmd.com/women/guide/normal-testosterone-and-estrogen-levels-in-women?page=2 | title=Normal Testosterone and Estrogen Levels in Women | publisher=WebMD | work=Website | access-date=28 October 2015}}</ref>

===Circulatory system===
Women have lower [[hematocrit]] (the volume percentage of [[red blood cell]]s in blood) than men; this is due to lower testosterone, which stimulates the production of [[erythropoietin]] by the kidney. The normal hematocrit level for a woman is 36% to 48% (for men, 41% to 50%). The normal level of [[hemoglobin]] (an oxygen-transport [[protein]] found in red blood cells) for women is 12.0 to 15.5 g/dL (for men, 13.5 to 17.5 g/dL).<ref>{{Cite web|url=https://www.redcrossblood.org/donate-blood/dlp/hematocrit.html|title=Hematocrit|website=www.redcrossblood.org}}</ref><ref>{{Cite journal|title=Comparisons of Blood Parameters, Red Blood Cell Deformability and Circulating Nitric Oxide Between Males and Females Considering Hormonal Contraception: A Longitudinal Gender Study - PMC|year=2018 |pmc=6305760 |last1=Grau |first1=M. |last2=Cremer |first2=J. M. |last3=Schmeichel |first3=S. |last4=Kunkel |first4=M. |last5=Bloch |first5=W. |journal=Frontiers in Physiology |volume=9 |page=1835 |doi=10.3389/fphys.2018.01835 |pmid=30618840 |doi-access=free }}</ref><ref>{{Cite web|url=https://www.mayoclinic.org/symptoms/high-red-blood-cell-count/basics/definition/sym-20050858|title=High red blood cell count|website=Mayo Clinic}}</ref>

Women's [[heart]]s have finer-grained textures in the muscle compared to men's hearts, and the [[Cardiac muscle|heart muscle]]'s overall shape and surface area also differs to men's when controlling for body size and age.<ref>{{Cite web|url=https://www.bhf.org.uk/what-we-do/news-from-the-bhf/news-archive/2020/august/esc-heart-shape-structure-men-women-qmul|title=Architecture of the heart different between women and men and with age|website=www.bhf.org.uk}}</ref><ref>{{Cite web|url=https://www.lahey.org/article/differences-between-mens-and-womens-hearts/|title=Differences Between Men's and Women's Hearts|date=February 21, 2019|website=Lahey Health}}</ref> In addition, women's hearts age more slowly compared to men's hearts.<ref>{{Cite web|url=https://www.hopkinsmedicine.org/news/media/releases/male_and_female_hearts_dont_grow_old_the_same_way|title=Male and Female Hearts Don't Grow Old the Same Way - 10/20/2015|website=www.hopkinsmedicine.org}}</ref>

=== Sex distribution ===
{{Main|Life expectancy#Sex differences}}Girls are born slightly less frequently than boys (the ratio is around 1:1.05).  Out of the total human population in 2015, there were 1018 men for every 1000 women.<ref>{{cite book |url=https://unstats.un.org/unsd/demographic-social/products/dyb/dybsets/2015.pdf |title=2015 Demographic Yearbook |author=[[United Nations]] |publication-place=New York |year=2016 |language=en, fr |page=60 |isbn=978-9210511094 |oclc=1028121211 |access-date=29 July 2022 |archive-url=https://web.archive.org/web/20210222114154/https://unstats.un.org/unsd/demographic-social/products/dyb/dybsets/2015.pdf |archive-date=22 February 2021 |url-status=live |publisher=United Nations Publication}}</ref>

=== Intersex women ===
{{Main|Intersex}}[[Intersex]] women have an intersex condition, [[Definitions of intersex|usually defined]] as those born with [[Sex organ|ambiguous genitalia]]. Most individuals with ambiguous genitalia [[Definitions of intersex#Assigned sex|are assigned]] female at birth, and most intersex women are [[cisgender]]. The medical practices to assign [[gender binary|binary]] female to intersex youth is often [[intersex human rights|controversial]].<ref name="Dreger-2009">{{cite journal |last1=Dreger |first1=Alice D. |last2=Herndon |first2=April M. |title=Progress and Politics in the Intersex Rights Movement: Feminist Theory in Action |journal=GLQ |date=2009 |volume=15 |issue=2 |pages=199–224 |id={{Project MUSE|261479}} |doi=10.1215/10642684-2008-134 }}</ref> Some intersex conditions are associated with typical rates of female [[gender identity]], while others are associated with substantially [[Intersex and LGBT|higher rates]] of identifying as [[LGBT]] compared to the general population.<ref>{{cite journal |last1=Hines |first1=Melissa |last2=Ahmed |first2=S. Faisal |last3=Hughes |first3=Ieuan A. |title=Psychological Outcomes and Gender-Related Development in Complete Androgen Insensitivity Syndrome |journal=Archives of Sexual Behavior |date=2003 |volume=32 |issue=2 |pages=93–101 |doi=10.1023/A:1022492106974 |pmid=12710824 }}</ref><ref>{{cite journal |last1=Cohen-Kettenis |first1=PT |title=Gender change in 46,XY persons with 5alpha-reductase-2 deficiency and 17beta-hydroxysteroid dehydrogenase-3 deficiency. |journal=Archives of Sexual Behavior |date=August 2005 |volume=34 |issue=4 |pages=399–410 |doi=10.1007/s10508-005-4339-4 |pmid=16010463 }}</ref><ref>{{cite journal |last1=Furtado |first1=Paulo Sampaio |last2=Moraes |first2=Felipe |last3=Lago |first3=Renata |last4=Barros |first4=Luciana Oliveira |last5=Toralles |first5=Maria Betânia |last6=Barroso |first6=Ubirajara |title=Gender dysphoria associated with disorders of sex development |journal=Nature Reviews Urology |date=November 2012 |volume=9 |issue=11 |pages=620–627 |doi=10.1038/nrurol.2012.182 |pmid=23045263 }}</ref><ref>{{cite web | url=https://www.thetrevorproject.org/wp-content/uploads/2021/12/Intersex-Youth-Mental-Health-Report.pdf | title = The Mental Health and Well-being of LGBTQ Youth who are Intersex | work = [[The Trevor Project]] | date = 2021}}</ref>