Breast: Difference between revisions

| Caption    = [[Morphology (biology)|Morphology]] of female human breasts, with the [[areola]], [[nipple]], and [[inframammary fold]]

The '''breasts''' are two prominences located on the upper [[ventral]] region of the [[torso]] among humans and other [[primate]]s. Both sexes develop breasts from the same [[embryology|embryological]] [[Tissue (biology)|tissues]]. The relative size and [[development of the breasts]] is a major [[secondary sex distinction]] between females and males. There is also considerable [[Bra size|variation in size]] between individuals. Permanent breast growth during [[puberty]] is caused by [[estrogens]] in conjunction with the [[growth hormone]]. Female humans are the only [[mammal]]s that permanently develop breasts at puberty; all other mammals develop their [[mammary tissue]] during the latter period of [[pregnancy]].  

{{cite web |url = http://www.merriam-webster.com/dictionary/breast |title = Breast – Definition of breast |work = Merriam-Webster |access-date = 21 October 2015 |archive-url = https://web.archive.org/web/20150906013636/http://www.merriam-webster.com/dictionary/breast |archive-date = 6 September 2015 |url-status = live |df = dmy-all }}</ref> [[Subcutaneous fat]] covers and envelops a network of [[lactiferous duct|ducts]] that converge on the [[nipple]], and these tissues give the breast its distinct size and globular shape. At the ends of the ducts are lobules, or clusters of [[Mammary alveolus|alveoli]], where milk is produced and stored in response to [[hormone|hormonal signals]].<ref name=SEER>

{{cite web |title = SEER Training: Breast Anatomy |url = http://training.seer.cancer.gov/breast/anatomy/ |publisher = National Cancer Institute |access-date = 9 May 2012 |archive-url = https://web.archive.org/web/20120502155537/http://training.seer.cancer.gov/breast/anatomy/ |archive-date = 2 May 2012 |url-status = live |df = dmy-all }}

The English word ''breast'' derives from the [[Old English]] word {{lang|ang|brēost}} {{Gloss|breast, bosom}} from [[Proto-Germanic]] {{lang|gem-x-proto|breustam}} {{Gloss|breast}}, from the [[Proto-Indo-European]] base {{lang|ine-x-proto|bhreus–}} {{Gloss|to swell, to sprout}}.<ref>{{cite web |title=Indo-European Lexicon |url=http://www.utexas.edu/cola/centers/lrc/ielex/PokornyMaster-X.html |url-status=dead |archive-url=https://web.archive.org/web/20160420225029/http://www.utexas.edu/cola/centers/lrc/ielex/PokornyMaster-X.html |archive-date=20 April 2016 |website=The University of Texas at Austin }}</ref> The ''breast'' spelling conforms to the Scottish and North English dialectal pronunciations.<ref>

A link has been proposed to processes for synthesizing the [[endogenous]] [[steroid hormone]] precursor [[dehydroepiandrosterone]] which takes place in fat rich regions of the body like the buttocks and breasts. These contributed to human brain development and played a part in increasing brain size.  Breast enlargement may for this purpose have occurred as early as ''[[Homo ergaster]]'' (1.7–1.4 [[myr|MYA]]).<ref name=":2" /> Other breast formation hypotheses may have then taken over as principal drivers.<ref>{{Cite journal|last1=LeBlanc|first1=Steven A.|last2=Barnes|first2=Ethne|date=July 1974|title=On the Adaptive Significance of the Female Breast|url=http://dx.doi.org/10.1086/282935|journal=The American Naturalist|volume=108|issue=962|pages=577–578|doi=10.1086/282935|bibcode=1974ANat..108..577L |s2cid=85243414|issn=0003-0147|access-date=24 November 2021|archive-date=4 March 2022|archive-url=https://web.archive.org/web/20220304004849/https://www.journals.uchicago.edu/doi/10.1086/282935|url-status=live|url-access=subscription}}</ref><ref name=":1">{{Cite journal|last1=Howard|first1=Beatrice A.|last2=Veltmaat|first2=Jacqueline M.|date=18 May 2013|title=Embryonic Mammary Gland Development; a Domain of Fundamental Research with High Relevance for Breast Cancer Research|journal=Journal of Mammary Gland Biology and Neoplasia|volume=18|issue=2|pages=89–91|doi=10.1007/s10911-013-9296-2|pmid=23686554|s2cid=1657065|issn=1083-3021|doi-access=free}}</ref><ref name=":2">{{Cite journal|last1=Pawłowski|first1=Bogusław|last2=Żelaźniewicz|first2=Agnieszka|date=2021|title=The evolution of perennially enlarged breasts in women: a critical review and a novel hypothesis|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/brv.12778|journal=Biological Reviews|language=en|volume=96|issue=6|pages=2794–2809|doi=10.1111/brv.12778|pmid=34254729|s2cid=235807642|issn=1469-185X|access-date=30 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130190318/https://onlinelibrary.wiley.com/doi/abs/10.1111/brv.12778|url-status=live|url-access=subscription}}</ref>

[[Morphology (biology)|Morphologically]], the breast is tear-shaped.<ref name="love_c1">{{cite book|last1=Love|first1=Susan M.|title=Dr. Susan Love's Breast Book|date=2015|publisher=Da Capo Press|location=U.S.|isbn=978-07382-1821-2|edition=6|chapter=1}}</ref> The superficial tissue layer ([[superficial fascia]]) is separated from the skin by 0.5–2.5&nbsp;cm of subcutaneous fat (adipose tissue). The [[Cooper's ligaments|suspensory Cooper's ligaments]] are fibrous-tissue prolongations that radiate from the superficial fascia to the skin envelope. The female adult breast contains 14–18 irregular lactiferous lobes that converge at the nipple. The 2.0–4.5&nbsp;mm milk ducts are immediately surrounded with dense connective tissue that support the glands. Milk exits the breast through the nipple, which is surrounded by a pigmented area of skin called the areola. The size of the areola can vary widely among women. The areola contains modified [[sebaceous gland|sweat glands]] known as [[Areolar gland|Montgomery's glands]]. These glands secrete oily fluid that lubricate and protect the nipple during breastfeeding.<ref name=stoppler>{{cite web |last1 = Stöppler |first1 = Melissa Conrad |title = Breast Anatomy |url = http://www.medicinenet.com/breast_anatomy/article.htm |access-date = 28 June 2015 |archive-url = https://web.archive.org/web/20150627065040/http://www.medicinenet.com/breast_anatomy/article.htm |archive-date = 27 June 2015 |url-status = live |df = dmy-all }}</ref> Volatile compounds in these secretions may also serve as an olfactory stimulus for the newborn's appetite.<ref>{{cite journal |doi = 10.1371/journal.pone.0007579 |title = The Secretion of Areolar (Montgomery's) Glands from Lactating Women Elicits Selective, Unconditional Responses in Neonates |year = 2009 |editor1-last = Hausberger |editor1-first = Martine |last1 = Doucet |first1 = Sébastien |last2 = Soussignan |first2 = Robert |last3 = Sagot |first3 = Paul |last4 = Schaal |first4 = Benoist |journal = PLOS ONE |volume = 4 |issue = 10 |pages = e7579 |pmid = 19851461 |pmc = 2761488 |bibcode = 2009PLoSO...4.7579D |doi-access = free }}</ref>

The dimensions and weight of the breast vary widely among women. A small-to-medium-sized breast weighs 500&nbsp;grams (1.1 pounds) or less, and a large breast can weigh approximately 750 to 1,000 grams (1.7 to 2.2 pounds) or more. In terms of composition, the breasts are about 80 to 90% [[stroma (tissue)|stroma]]l tissue ([[adipose tissue|fat]] and [[connective tissue]]), while [[epithelial tissue|epithelial]] or [[gland]]ular tissue only accounts for about 10 to 20% of the volume of the breasts.<ref name="pmid16728564">{{cite journal |vauthors=Lorincz AM, Sukumar S |title=Molecular links between obesity and breast cancer |journal=Endocrine-Related Cancer |volume=13 |issue=2 |pages=279–92 |year=2006 |pmid=16728564 |doi=10.1677/erc.1.00729 |quote=Adipocytes make up the bulk of the human breast, with epithelial cells accounting for only approximately 10% of human breast volume.|doi-access=free}}</ref><ref name="pmid11149569">{{cite journal |vauthors=Howard BA, Gusterson BA |title=Human breast development |journal=Journal of Mammary Gland Biology and Neoplasia |volume=5 |issue=2 |pages=119–37 |year=2000 |pmid=11149569 |doi= 10.1023/A:1026487120779|s2cid=10819224 |quote=In the stroma, there is an increase in the amount of fibrous and fatty tissue, with the adult nonlactating breast consisting of 80% or more of stroma.}}</ref><ref name="RosenfieldCookeRadovick2021">{{cite book | title = Sperling Pediatric Endocrinology | last1 = Rosenfield | first1 = Robert L. | last2 = Cooke | first2 = David W. | last3 = Radovick | first3 = Sally | chapter = Puberty in the Female and Its Disorders | date = 2021 | pages = 528–626 | publisher = Elsevier | doi = 10.1016/B978-0-323-62520-3.00016-6 | isbn = 9780323625203 | s2cid = 234131890 | chapter-url = https://books.google.com/books?id=8J7yDwAAQBAJ&pg=PA554 | quote = Estrogen stimulates the nipples to grow, mammary terminal duct branching to progress to the stage at which ductules are formed, and fatty stromal growth to increase until it constitutes about 85% of the mass of the breast. [...] Lobulation appears around menarche, when multiple blind saccular buds form by branching of the terminal ducts. These effects are due to the presence of progesterone. [...] Full alveolar development normally only occurs during pregnancy under the influence of additional progesterone and prolactin.}}</ref><ref name="pmid22206682">{{cite journal |vauthors=Hagisawa S, Shimura N, Arisaka O |title=Effect of excess estrogen on breast and external genitalia development in growth hormone deficiency |journal=Journal of Pediatric and Adolescent Gynecology |volume=25 |issue=3 |pages=e61–3 |year=2012 |pmid=22206682 |doi=10.1016/j.jpag.2011.11.005 |quote=Estrogen stimulates growth of the nipples, progression of mammary duct branching to the stage at which ductiles are formed, and fatty stromal growth until it constitutes about 85% of the mass of the breast.}}</ref><ref name="pmid2942075">{{cite journal | vauthors = Drife JO | title = Breast development in puberty | journal = Ann N Y Acad Sci | volume = 464 | issue = 1| pages = 58–65 | date = 1986 | pmid = 2942075 | doi = 10.1111/j.1749-6632.1986.tb15993.x | bibcode = 1986NYASA.464...58D | s2cid = 12735704 | url = | quote = Along with the glandular growth, there is an increase in the amount of fibrous and fatty tissue, and in fact these latter two constituents of the breast account for a far greater proportion of the morphologic growth than the proportion contributed by glandular tissue. In the nonlactating adult breast, glandular tissue accounts for no more than 20% of the breast volume, and often much less than this, and the morphologic changes at puberty are therefore mainly due to stromal expansion.}}</ref> The tissue composition ratios of the breast also vary among women. Some women's breasts have a higher proportion of glandular tissue than of adipose or [[connective tissue|connective]] tissues. The fat-to-connective-tissue ratio determines the density or firmness of the breast. During a woman's life, her breasts change size, shape, and weight due to hormonal changes during [[thelarche|puberty]], the [[menstruation|menstrual cycle]], [[Maternal physiological changes in pregnancy|pregnancy]], breastfeeding, and [[menopause]].<ref>Pamplona DC, de Abreu Alvim C. Breast Reconstruction with Expanders and Implants: a Numerical Analysis. Artificial Organs 8 (2004), pp. 353–356.</ref><ref>{{cite journal |last1 = Grassley |first1 = JS |year = 2002 |title = Breast Reduction Surgery: What every Woman Needs to Know |journal = Lifelines |volume = 6 |issue = 3 |pages = 244–249 |doi = 10.1111/j.1552-6356.2002.tb00088.x |pmid = 12078570 }}</ref>

{{Multiple image

| image1            = Breasts of a woman.jpg

| image2            = Breasts, young woman.png

| footer            = Breasts can vary significantly in both size and shape.

| direction        = horizontal

| image3            = Small Breasts.jpg

| perrow            = 2 / 2

| total_width      = 320

| image4            = Breasts close-up (4).jpg

}}

The morphologic variations in the size, shape, volume, tissue density, pectoral locale, and spacing of the breasts determine their natural shape, appearance, and position on a woman's chest. [[Breast size]] and other characteristics do not predict the fat-to-milk-gland ratio or the potential for the woman to nurse an infant. The size and the shape of the breasts are influenced by normal-life hormonal changes (thelarche, menstruation, pregnancy, menopause) and medical conditions (e.g. [[virginal breast hypertrophy]]).<ref name=wood>{{cite journal |vauthors = Wood K, Cameron M, Fitzgerald K |title = Breast Size, Bra Fit and Thoracic Pain in Young Women: A Correlational Study |journal = Chiropractic & Osteopathy |volume = 16 |article-number = 1 |year = 2008 |pmid = 18339205 |pmc = 2275741 |doi = 10.1186/1746-1340-16-1 |doi-access = free }}</ref> The shape of the breasts is naturally determined by the support of the suspensory Cooper's ligaments, the underlying muscle and bone structures of the chest, and by the skin envelope. The suspensory ligaments sustain the breast from the clavicle (collarbone) and the clavico-pectoral fascia (collarbone and chest) by traversing and encompassing the fat and milk-gland tissues. The breast is positioned, affixed to, and supported upon the chest wall, while its shape is established and maintained by the skin envelope.<ref>{{Cite web |title=Breast Anatomy – Breast360.org {{!}} The American Society of Breast Surgeons Foundation |url=https://breast360.org/topic/2017/01/01/breast-anatomy/ |access-date=2024-12-21 |website=breast360.org}}</ref><ref>{{Cite web |title=Breast Anatomy {{!}} SEER Training |url=https://training.seer.cancer.gov/breast/anatomy/ |access-date=2024-12-21 |website=training.seer.cancer.gov}}</ref> In most women, one breast is slightly larger than the other.<ref name=love_c1/> More obvious and persistent asymmetry in breast size occurs in up to 25% of women.<ref name=mgh2010>{{cite web |url = http://www.mgh.harvard.edu/children/adolescenthealth/articles/aa_breast_development.aspx |title = Breast Development |publisher = Massachusetts Hospital for Children |access-date = 2 June 2010 |archive-url = https://web.archive.org/web/20101225165742/http://www.mgh.harvard.edu/children/adolescenthealth/articles/aa_breast_development.aspx |archive-date = 25 December 2010 |url-status = dead |df = dmy }}</ref>

 

Breasts have been categorized into four general morphological groups:  "flat, spheric, protruded, and drooped", or "small/flat, large/inward, upward, and droopy".<ref>{{Cite journal |last1=Suh |first1=Minyoung |last2=Park |first2=Jung Hyun |date=2022-01-01 |title=Breast Geometry Characterization of Young American Females Using 3D Image Analysis |journal=Applied Sciences |language=en |volume=12 |issue=17 |pages=8578 |doi=10.3390/app12178578 |doi-access=free |issn=2076-3417}}</ref><ref>{{Cite journal |title=Brassiere Pattern Development Based on 3D Measurements of Upper Body Types for Women in Their 30's |url=https://koreascience.kr/article/JAKO200827464608269.page |journal=The Research Journal of the Costume Culture|date=2008 |volume=16 |issue=3 |last1=Mi-Sook |first1=Cho }}</ref><ref>{{Cite journal |last1=Coltman |first1=Celeste E. |last2=Steele |first2=Julie R. |last3=McGhee |first3=Deirdre E. |date=2018-09-02 |title=Effects of age and body mass index on breast characteristics: a cluster analysis |url=https://www.tandfonline.com/doi/abs/10.1080/00140139.2018.1481229 |journal=Celeste E. Coltman |volume=61 |issue=9 |pages=1232–1245 |doi=10.1080/00140139.2018.1481229 |pmid=29792567 |issn=0014-0139|url-access=subscription }}</ref>

[[Sports bra]]s are sometimes used for cardiovascular exercise, sports bras are designed to secure the breasts closely to the body to prevent movement during high-motion activity such as running. Studies have indicated sports bras which are overly tight may restrict respiratory function.<ref>{{Cite journal |last1=Ocran |first1=Francisca Margarita |last2=Ji |first2=Xiaofen |last3=Zhai |first3=Lina |date=January 2022 |title=A study to evaluate pressure distribution of different sports bras |journal=Journal of Engineered Fibers and Fabrics |language=en |volume=17 |doi=10.1177/15589250221118643 |issn=1558-9250|doi-access=free }}</ref><ref>{{Cite journal |last1=Kipp |first1=Shalaya |last2=Leahy |first2=Michael G. |last3=Sheel |first3=A. William |date=2024-06-01 |title=Sports Bra Restriction on Respiratory Mechanics during Exercise |journal=Medicine and Science in Sports and Exercise |volume=56 |issue=6 |pages=1168–1176 |doi=10.1249/MSS.0000000000003403 |issn=1530-0315 |pmid=38350462}}</ref>

The breasts are principally composed of adipose, [[glandular tissue|glandular]], and [[w:connective tissue|connective]] tissues.<ref name="yen">{{citation |title = Yen & Jaffe's Reproductive Endocrinology |author = Robert L. Barbieri |doi = 10.1016/B978-1-4160-4907-4.00010-3 |edition = 6th |publisher = Elsevier |date = 2009 |journal = Yen |pages = 235–248 |isbn = 978-1-4160-4907-4 |df = dmy-all |doi-access = free }}

</ref> Because these tissues have hormone receptors,<ref name="yen" /><ref name="gland activation">{{citation |title = Hormone Action in the Mammary Gland |author1 = Brisken |author2 = Malley |doi = 10.1101/cshperspect.a003178 |date = 2 December 2010 |pmid = 20739412 |pmc = 2982168 |volume = 2 |issue = 12 |journal = Cold Spring Harb Perspect Biol |pages = a003178 }}</ref> their sizes and volumes fluctuate according to the hormonal changes particular to thelarche (sprouting of breasts), menstruation (egg production), pregnancy (reproduction), lactation (feeding of offspring), and menopause (end of menstruation).

[[File:Transsexual HRT induced developed breasts.jpg|thumb|upright|A transgender woman with HRT-induced developed breasts.]]

During the menstrual cycle, the breasts are enlarged by [[premenstrual water retention]] and temporary growth as influenced by changing hormone levels.<ref name="mlpswelling">{{citation |title = Breast – premenstrual tenderness and swelling |url = https://www.medlineplus.gov/ency/article/003153.htm |publisher = A.D.A.M. |date = May 2012 |access-date = 21 March 2018 |archive-url = https://web.archive.org/web/20160705060104/https://www.nlm.nih.gov/medlineplus/ency/article/003153.htm |archive-date = 5 July 2016 |url-status = live |df = dmy-all }}

At menopause, breast atrophy occurs.<ref>{{Cite journal |title=Menopausal Transition, Body Mass Index, and Prevalence of Mammographic Dense Breasts in Middle-Aged Women |date=2020 |pmc=7465213 |last1=Kim |first1=E. Y. |last2=Chang |first2=Y. |last3=Ahn |first3=J. |last4=Yun |first4=J. S. |last5=Park |first5=Y. L. |last6=Park |first6=C. H. |last7=Shin |first7=H. |last8=Ryu |first8=S. |journal=Journal of Clinical Medicine |volume=9 |issue=8 |page=2434 |doi=10.3390/jcm9082434 |doi-access=free |pmid=32751482 }}</ref> The breasts can decrease in size when the levels of circulating estrogen decline. The adipose tissue and milk glands also begin to wither. The breasts can also become enlarged from [[Adverse effect|adverse side effects]] of [[combined oral contraceptive pill]]s. The size of the breasts can also increase and decrease in response to [[body weight|weight]] fluctuations.<ref>{{Cite journal |last1=Wanders |first1=Johanna Olga Pauline |last2=Bakker |first2=Marije Fokje |last3=Veldhuis |first3=Wouter Bernard |last4=Peeters |first4=Petra Huberdina Maria |last5=van Gils |first5=Carla Henrica |date=2015-05-30 |title=The effect of weight change on changes in breast density measures over menopause in a breast cancer screening cohort |journal=Breast Cancer Research |volume=17 |issue=1 |pages=74 |doi=10.1186/s13058-015-0583-2 |doi-access=free |issn=1465-542X |pmc=4487974 |pmid=26025139}}</ref>  

The primary function of the breasts, as mammary glands, is the nourishing of an infant with [[breast milk]]. Milk is produced in milk-secreting cells in the alveoli. When the breasts are stimulated by the suckling of her baby, the mother's brain secretes [[oxytocin]]. High levels of oxytocin trigger the contraction of muscle cells surrounding the alveoli, causing milk to flow along the ducts that connect the alveoli to the nipple.<ref name="NCBI Bookshelf 2008">{{cite web | title=The physiological basis of breastfeeding | website=NCBI Bookshelf | date=5 November 2008 | url=https://www.ncbi.nlm.nih.gov/books/NBK148970/ | access-date=13 February 2018 | archive-url=https://web.archive.org/web/20180119051121/https://www.ncbi.nlm.nih.gov/books/NBK148970/ | archive-date=19 January 2018 | url-status=live | df=dmy-all }}

{{cite web |author = World Health Organization |date = February 2006 |title = Fact sheet No. 297: Cancer |url =https://www.who.int/mediacentre/factsheets/fs297/en/index.html |access-date = 26 April 2007 |archive-url = https://web.archive.org/web/20140213212322/http://www.who.int/mediacentre/factsheets/fs297/en/index.html |archive-date = 13 February 2014 |url-status = live |df = dmy-all |author-link = World Health Organization }}</ref> and it is one of the leading causes of death among women. Factors that appear to be implicated in decreasing the risk of breast cancer are regular breast examinations by health care professionals, regular [[mammograms]], [[Breast self-examination|self-examination of breasts]], healthy diet, exercise to decrease excess body fat,<ref>

[[Plastic surgery]] can be performed to [[Breast augmentation|augment]] or [[Breast reduction|reduce]] the size of breasts, or to [[reconstructive surgery|reconstruct]] the breast in cases of deformative disease, such as [[breast cancer]].<ref>{{cite web |url = http://www.sexarchive.info/ATLAS_EN/html/secondary_characteristics.html |title = Secondary sex characteristics |publisher = .hu-berlin.de |access-date = 31 October 2011 |archive-url = https://web.archive.org/web/20130622035035/http://www.sexarchive.info/ATLAS_EN/html/secondary_characteristics.html |archive-date = 22 June 2013 |url-status = live |df = dmy-all }}

In [[Saint symbology|Christian iconography]], some works of art depict women with their breasts in their hands or on a platter, signifying that they died as a martyr by having their breasts severed; one example of this is [[Agatha of Sicily|Saint Agatha of Sicily]].<ref>{{cite web |title = St Agatha |url = http://www.catholic.org/saints/saint.php?saint_id=14 |publisher = Catholic Online |access-date = 27 December 2015 |archive-url = https://web.archive.org/web/20160304000129/http://www.catholic.org/saints/saint.php?saint_id=14 |archive-date = 4 March 2016 |url-status = live |df = dmy-all }}

[[Femen]] is a [[feminism|feminist]] activist group which uses [[topless protest]]s as part of their campaigns against [[sex tourism]]<ref name=FEMEN>[http://www.kyivpost.com/news/politics/detail/65379/ Femen wants to move from public exposure to political power] {{Webarchive|url=https://web.archive.org/web/20101207042451/http://www.kyivpost.com/news/politics/detail/65379 |date=7 December 2010 }}, ''[[Kyiv Post]]'' (28 April 2010)</ref><ref name="movements1">{{cite web |url = http://www.movements.org/case-study/entry/ukraines-ladies-of-femen/ |title = Ukraine's Ladies of Femen |publisher = Movements.org |date = 16 August 2011 |access-date = 22 April 2013 |url-status = usurped |archive-url = https://web.archive.org/web/20120414005441/http://www.movements.org/case-study/entry/ukraines-ladies-of-femen |archive-date = 14 April 2012 }}</ref> religious institutions,<ref name=BBCobservOct12>[https://www.bbc.co.uk/news/world-europe-20028797 Ukraine's Femen:Topless protests 'help feminist cause'] {{Webarchive|url=https://web.archive.org/web/20180412230110/http://www.bbc.co.uk/news/world-europe-20028797 |date=12 April 2018 }}, [[BBC News]] (23 October 2012)</ref> [[sexism]], and [[homophobia]].<ref>{{cite news |url = http://www.huffingtonpost.com/2013/04/24/topless-femen-protest-andre-jozef-leonard_n_3146609.html |title = Topless FEMEN Protesters Drench Belgian Archbishop André-Jozef Léonard, Protest Homophobia in Catholic Church (PHOTOS) |work = The Huffington Post |access-date = 23 March 2015 |date = 24 April 2013 |archive-url = https://web.archive.org/web/20150416042913/http://www.huffingtonpost.com/2013/04/24/topless-femen-protest-andre-jozef-leonard_n_3146609.html |archive-date = 16 April 2015 |url-status = live |df = dmy-all }}</ref> Femen activists have been regularly detained by police in response to their protests.<ref name=BBCTunis>[https://www.bbc.co.uk/news/world-africa-22881163 Femen activists jailed in Tunisia for topless protest] {{Webarchive|url=https://web.archive.org/web/20180827210121/https://www.bbc.co.uk/news/world-africa-22881163 |date=27 August 2018 }}, [[BBC News]] (12 June 2013)</ref>

[[File:Beauty revealed.jpg|thumb|''[[Beauty Revealed]]'', 1828 self-portrait by the American artist [[Sarah Goodridge]].]]

[[File:Namibie Himba 0716a.jpg|thumb|left|upright|A bare-breasted [[Himba people|Himba]] woman of northern Namibia wears a traditional headdress and skirt]]

 

Because breasts are mostly fatty tissue, their shape can—within limits—be molded by clothing, such as [[foundation garment]]s. [[Bra]]s are commonly worn by about 90% of Western women,<ref>{{cite web |url = http://www.1stbras.com/bra-cup-sizes.php |archive-url = https://web.archive.org/web/20160308210937/http://www.1stbras.com/bra-cup-sizes.php |url-status = usurped |archive-date = 8 March 2016 |title = Bra Cup Sizes—getting fitted with the right size |publisher = 1stbras.com |access-date = 11 May 2010 }}</ref><ref>{{cite web |url = http://www.liv.com/right_bra.php |archive-url = https://web.archive.org/web/20090328083521/http://www.liv.com/right_bra.php |url-status = dead |archive-date = 28 March 2009 |title = The Right Bra |publisher = Liv.com |access-date = 11 May 2010 }}</ref><ref>{{cite news |url = https://www.independent.co.uk/news/uk/this-britain/breast-supporting-act-a-century-of-the-bra-5334510.html |title = Breast supporting act: a century of the bra |date = 15 August 2007 |publisher = The Independent UK |access-date = 11 May 2010 |location = London |archive-url = https://web.archive.org/web/20160305101134/http://www.independent.co.uk/news/uk/this-britain/breast-supporting-act-a-century-of-the-bra-5334510.html |archive-date = 5 March 2016 |url-status = live |df = dmy-all }}</ref> and are often worn for support.<ref>{{cite journal |pmc = 2275741 |pmid = 18339205 |doi = 10.1186/1746-1340-16-1 |volume = 16 |title = Breast size, bra fit and thoracic pain in young women: a correlational study |year = 2008 |journal = Chiropr Osteopat |article-number = 1 |last1 = Wood |first1 = K |last2 = Cameron |first2 = M |last3 = Fitzgerald |first3 = K |doi-access = free }}</ref> The [[social norm]] in most [[Western culture]]s is to cover breasts in public, though the extent of coverage varies depending on the social context. Some religions ascribe a special status to the female breast, either in formal teachings or through symbolism.<ref>{{cite journal |title=Worshipping Breasts in the Maternal Landscape of India |journal=South Asian Studies |date=27 October 2015 |volume=31 |issue=2015 |doi=10.1080/02666030.2015.1094209 |url=https://www.tandfonline.com/doi/full/10.1080/02666030.2015.1094209 |access-date=30 September 2020 |last1=Bohidar |first1=Anannya |pages=247–253 |s2cid=194282633 |archive-date=2 January 2021 |archive-url=https://web.archive.org/web/20210102165529/https://www.tandfonline.com/doi/full/10.1080/02666030.2015.1094209 |url-status=live |url-access=subscription }}</ref> [[Islam]] forbids free women from exposing their breasts in public.

Social attitudes and laws regarding [[breastfeeding in public]] vary widely. In many countries, breastfeeding in public is common, legally protected, and generally not regarded as an issue. However, even though the practice may be legal or socially accepted, some mothers may nevertheless be reluctant to expose a breast in public to breastfeed<ref>{{cite journal|doi=10.1186/1746-4358-3-11|title=Got milk? Not in public!|pmid=18680578|year=2008|last1=Wolf|first1=J.H.|volume=3|issue=1|page=11|pmc=2518137|journal=International Breastfeeding Journal |doi-access=free }}</ref><ref name=Vance_2005>{{cite journal | last = Vance | first = Melissa R. | title = Breastfeeding Legislation in the United States: A General Overview and Implications for Helping Mothers | journal = LEAVEN | volume = 41 | issue = 3 | pages = 51–54 | date = June–July 2005 | url = http://www.llli.org/llleaderweb/LV/LVJunJul05p51.html | url-status = dead | archive-url = https://web.archive.org/web/20070331220518/http://www.llli.org/llleaderweb/LV/LVJunJul05p51.html | archive-date = 31 March 2007}}</ref> due to actual or potential objections by other people, negative comments, or harassment.<ref name=Jordan_2002>{{cite book|editor-last=Jordan|editor-first=Tim|editor-last2=Pile|editor-first2=Steve|title=Social Change|page=[https://archive.org/details/socialchange0000unse/page/233 233]|publisher=Blackwell|year=2002|isbn=9780631233114|url=https://archive.org/details/socialchange0000unse/page/233}}</ref> It is estimated that around 63% of mothers across the world have publicly breast-fed.<ref>{{Cite book|title = Breast Feeding With Confidence|last = Cox|first = Sue|publisher = Meadowbrook Press|year = 2002|isbn = 0684040050|location = United States|url-access = registration|url = https://archive.org/details/breastfeedingwit00suec}}</ref> Bare-breasted women are legal and culturally acceptable at public beaches in Australia and much of Europe.<ref>{{Cite journal |last=Bennett |first=Theodore |title=Clothing Optional?: Nudity and the Law of the Australian Beach |url=https://doaj.org/article/3c5619e831254faca2c5e8cc6f9a617b |journal=Bond Law Review |language=en |issn=2202-4824}}</ref><ref name=":3" /> Filmmaker [[Lina Esco]] made a film entitled ''[[Free the Nipple (film)|Free the Nipple]]'', which is about "...laws against female toplessness or restrictions on images of female, but not male, nipples", which Esco states is an example of [[sexism]] in society.<ref name="thedailybeast.com">{{cite news |url = http://www.thedailybeast.com/articles/2014/09/09/women-it-s-time-to-reclaim-our-breasts.html |title = Women, It's Time to Reclaim Our Breasts |first = Emily |last = Shire |date = 9 September 2014 |newspaper = The Daily Beast |access-date = 11 December 2016 |archive-url = https://web.archive.org/web/20161101085547/http://www.thedailybeast.com/articles/2014/09/09/women-it-s-time-to-reclaim-our-breasts.html |archive-date = 1 November 2016 |url-status = live |df = dmy-all }}</ref>

In some cultures, breasts play a role in [[human sexual activity]]. Breasts and especially the nipples are among the various human [[erogenous zone]]s. They are sensitive to the touch as they have many nerve endings; and it is common to press or [[massage]] them with hands or [[stimulation of nipples|orally]] before or during sexual activity. During [[sexual arousal]], breast size increases, [[vein|venous]] patterns across the breasts become more visible, and nipples harden.{{Citation needed|date=December 2024}} Compared to other primates, human breasts are proportionately large throughout adult females' lives. Some writers have suggested that they may have evolved as a visual signal of sexual maturity and fertility.<ref>{{cite journal |author = Anders Pape Møller |title = Breast asymmetry, sexual selection, and human reproductive success |journal = Ethology and Sociobiology |year = 1995 |volume = 16 |issue = 3 |pages = 207–219 |doi = 10.1016/0162-3095(95)00002-3 |display-authors = 1 |last2 = Soler |first2 = M |last3 = Thornhill |first3 = R }}</ref> In ''[[Patterns of Sexual Behavior]]'', a 1951 analysis of 191 traditional cultures, the researchers noted that stimulation of the female breast by a male sexual partner "seemed absent in all subhuman forms, although it is common among the members of many different human societies."<ref>{{Cite book |last=Clellan S. Ford and Frank A. Beach |url=http://archive.org/details/patternsofsexual0000clel_d2x3 |title=Patterns of Sexual Behaviour |date=1965 |others=Internet Archive |pages=70}}</ref>

Many people regard bare female breasts to be aesthetically pleasing or [[erotic]], and they can elicit heightened [[sexual desire]]s in men in many cultures. In the [[History of India|ancient Indian]] work the ''[[Kama Sutra]]'', light scratching of the breasts with nails and biting with teeth are considered erotic.<ref>{{cite web |url = http://www.sacred-texts.com/sex/kama/index.htm |title = Sir Richard Burton's English translation of Kama Sutra |publisher = Sacred-texts.com |access-date = 31 October 2011 |archive-url = https://web.archive.org/web/20100102051149/http://sacred-texts.com/sex/kama/index.htm |archive-date = 2 January 2010 |url-status = live |df = dmy }}</ref> Some people show a [[sexual interest]] in female breasts distinct from that of the person, which may be regarded as a [[breast fetish]].<ref>Hickey, Eric W. (2003). Encyclopaedia of Murder and Violent Crime. Sage Publications Inc. {{ISBN|978-0-7619-2437-1}}</ref> A number of Western fashions include clothing which accentuate the breasts, such as the use of [[push-up bra]]s and [[decollete]] (plunging neckline) gowns and blouses which show [[cleavage (breasts)|cleavage]]. While U.S. culture prefers breasts that are youthful and upright, some cultures venerate women with drooping breasts, indicating mothering and the wisdom of experience.<ref>{{cite book |last = Burns-Ardolino |first = Wendy |title = Jiggle: (Re)shaping American women |year = 2007 |publisher = Lexington Books |location = Lanham, MD |isbn = 978-0-7391-1299-1 |page = 31 }}</ref>

Research conducted at the [[Victoria University of Wellington]] showed that breasts are often the first thing men look at, and for a longer time than other body parts.<ref name=ASB>{{cite journal |last1 = Dixson |first1 = BJ |last2 = Grimshaw |first2 = GM |last3 = Linklater |first3 = WL |last4 = Dixson |first4 = AF |title = Eye-tracking of men's preferences for waist-to-hip ratio and breast size of women |journal = [[Archives of Sexual Behavior]] |volume = 40 |issue = 1 |pages = 43–50 |publisher = [[International Academy of Sex Research]] |date = February 2011 |doi = 10.1007/s10508-009-9523-5 |pmid = 19688590 |s2cid = 4997497 }}</ref> The writers of the study had initially speculated that the reason for this is due to [[endocrinology]] with larger breasts indicating higher levels of estrogen and a sign of greater fertility,<ref name=ASB /><ref name=BBC>{{cite news |url = http://news.bbc.co.uk/2/hi/health/3682657.stm |title = Hourglass figure fertility link |work = BBC News |date = 4 May 2004 |access-date = 31 October 2011 |archive-url = https://web.archive.org/web/20111011122830/http://news.bbc.co.uk/2/hi/health/3682657.stm |archive-date = 11 October 2011 |url-status = live |df = dmy-all }}</ref> but the researchers said that "Men may be looking more often at the breasts because they are simply aesthetically pleasing, regardless of the size."<ref name=ASB />

* {{cite book | last=Lawrence | first=Ruth | title=Breastfeeding : a guide for the medical profession, 8th edition | publisher=Elsevier | location=Philadelphia, PA | year=2016 | isbn=978-0-323-35776-0 }}