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A boy is a young male human. The term is commonly used for a child or an adolescent. When a male human reaches adulthood, he is usually described as a man.

According to the Merriam-Webster Dictionary, a boy is "a male child from birth to adulthood".^[1]

The word "boy" comes from Middle English boi, boye ("boy, servant"), related to other Germanic words for boy, namely East Frisian boi ("boy, young man") and West Frisian boai ("boy"). Although the exact etymology is obscure, the English and Frisian forms probably derive from an earlier Anglo-Frisian *bō-ja ("little brother"), a diminutive of the Germanic root *bō- ("brother, male relation"), from Proto-Indo-European *bhā-, *bhāt- ("father, brother"). The root is also found in Norwegian dialectal boa ("brother"), and, through a reduplicated variant *bō-bō-, in Old Norse bófi, Dutch boef "(criminal) knave, rogue", German Bube ("knave, rogue, boy"). Furthermore, the word may be related to Bōia, an Anglo-Saxon personal name.^[2]

Historically,^[when?] in the United States and South Africa, "boy" was used not only for domestic servants but also more generally as a disparaging term for black men; the term implied a subservient status.^[3][4][5][6] Thomas Branch, an early African-American Seventh-day Adventist missionary to Nyassaland (Malawi) referred to the native students as "boys":

There is one way by which we judge many of our present boys to be quite different from some of those who were here long ago: those that are married have their wives here with them, and build their own houses, and all are busy making their gardens. I have told all the boys that if they wished to stay here and learn, those that had wives must bring them.^[7]

Multiple politicians – including New Jersey Governor Chris Christie and former Kentucky Congressman Geoff Davis – have been criticized publicly for referring to a black man as "boy".^[5][6]

During an event promoting the 2017 boxing bout between Floyd Mayweather Jr. and Conor McGregor, the latter told the former to "dance for me, boy."^[8] The remarks led several boxers – including Mayweather and Andre Ward – as well as multiple commentators to accuse McGregor of racism.^{[8][9][10][11]}

Human sex is determined at fertilization when the genetic sex of the zygote is determined by whether the sperm cell contains an X or Y chromosome. If the sperm cell contains an X chromosome, the fetus will be XX and, typically, a girl will develop. A sperm cell carrying a Y chromosome results in an XY combination, and typically a boy will develop. Variations from this general rule result in intersex fetuses.^[12]

In male embryos at six to seven weeks' gestation, "the expression of a gene on the Y chromosome induces changes that result in the development of the testes". At approximately nine weeks' gestation, the production of testosterone by a male embryo results in the development of the male reproductive system.^[13]

The male reproductive system includes both external and internal organs. The external organs include the penis, the scrotum, and the testicles (or testes). The penis is a cylindrical organ filled with spongy tissue. It is the organ used by boys to expel urine. The foreskin of some boys' penises is removed in a process known as circumcision. The scrotum is a loose sac of skin behind the penis which contains the testicles. Testicles are oval-shaped gonads. A boy generally possesses two testicles. Internal male reproductive organs include the vas deferens, the ejaculatory ducts, the urethra, the seminal vesicles, and the prostate gland.^[14][15]

Puberty is the process by which children's bodies mature into adult bodies that are capable of reproduction. On average, boys begin puberty at ages 11–12 and complete puberty at ages 16–17.^[16][17]

In boys, puberty begins with the enlargement of the testicles and scrotum. The penis also increases in size, and a boy develops pubic hair. A boy's testicles also begin making sperm. The release of semen, which contains sperm and other fluids, is called ejaculation.^[18] During puberty, a boy's erect penis becomes capable of ejaculating semen and impregnating a female.^[14][15] A boy's first ejaculation is an important milestone in his development.^[19] On average, a boy's first ejaculation occurs at age 13.^[20] Ejaculation sometimes occurs during sleep; this phenomenon is known as a nocturnal emission.^[18]

When a boy reaches puberty, testosterone triggers the development of secondary sex characteristics. A boy's muscles increase in size and mass, his voice deepens, his bones lengthen, and the shape of his face and body changes.^[21] The increased secretion of testosterone from the testicles during puberty causes the male secondary sexual characteristics to be manifested.^[22] Male secondary sex characteristics include:

• Growth of body hair, including underarm, abdominal, chest, and pubic hair.^[23][21]
• Growth of facial hair.^[21]
• Enlargement of larynx (Adam's apple) and deepening of voice.^[21][24]
• Increased stature; adult males are taller than adult females, on average.^[21]
• Heavier skull and bone structure.^[21]
• Increased muscle mass and strength.^[21]
• Broadening of shoulders and chest; shoulders wider than hips.^[25]
• Increased secretions of oil and sweat glands.^[24]

Boys across various age groups are often part of social circles that establish their own unique norms. These norms serve as a benchmark for boys to assess their peers. The adherence to these group norms often holds more weight than the mere affiliation to the group. In fact, boys who do not conform to these norms are often evaluated lower than those who, despite being strangers, conform to the group’s norms. This phenomenon underscores the powerful influence of group norms in shaping attitudes and actions, and the social implications of conformity.^[26][27][28] Boys who defy gender norms may face a higher risk of abuse, and may experience more depression than gender-conforming peers, as well as social stigma from parents^[29] and peers.^[30][31] The gender policing towards them can increase the risk of alcohol use, anxiety, and depression in adulthood.^[32]

In some cultures, the birth of a male child (boy) is considered prosperous.^[33]

Boys perform the majority of child labor around the world compared to girls; 88 million child laborers are boys and 64 million are girls. Boys are also the primary victims of hazardous child labor. They are mainly employed in the agriculture, construction and mining sectors. Boy workers also account for about 87 percent of those who died on the job between 2003 and 2016 in the US.^[34]

Boys are given a basic reading, writing and mathematics skill and then forced to pursue their father's profession in order to alleviate financial burden of the family. This is one of the main reasons why boys are preferred over girls by the rural communities in poor countries. In India, by contrast, the majority of adopted children are girls even though boys are preferred in general compared to girls.^[35][36][37]

• Boy band
• Shōnen manga
• Man

• Allen, Edward A. (1982). "Public School Elites in Early-Victorian England: The Boys at Harrow and Merchant Taylors' Schools from 1825 to 1850". Journal of British Studies. 21 (2): 87–117. doi:10.1086/385791. S2CID 144610133.
• Baggerman, Arianne; Dekker, Rudolf (2009). Child of the Enlightenment: Revolutionary Europe Reflected in a Boyhood Diary. Brill. ISBN 9789004273641.
• Clement, Priscilla Ferguson; Reinier, Jacqueline S., eds. (2001). Boyhood in America: an encyclopedia. 2 vol. ABC-CLIO. ISBN 978-1-57607-215-8.
• Fauci, Anthony S.; Braunwald, Eugene; Kasper, Dennis L.; Hauser, Stephen L.; Longo, Dan L.; Jameson, J. Larry; Loscalzo, Joseph (2008). Harrison's Principles of Internal Medicine (17th ed.). McGraw-Hill Medical. pp. 2339–2346. ISBN 9780071466332.
• Giese, Rachel (2018). Boys: What it Means to Become a Man. Seal Press. ISBN 9781443442916.
• Hunt, Peter (2004). International companion encyclopedia of children's literature. Routledge. ISBN 9780415290531.
• Illick, Joseph E. (2005). American childhoods. University of Pennsylvania Press. ISBN 9780812236590.
• Killian, Caitlin (2007). "Covered girls and savage boys: Representations of Muslim youth in France". Journal of Social and Ecological Boundaries. 3 (1): 69–90.
• Kugler, Adriana D.; Kumar, Santosh (2017). "Preference for boys, family size, and educational attainment in India". Demography. 54 (3): 835–859. doi:10.1007/s13524-017-0575-1. PMC 5486858. PMID 28484996.
• Liu, Fengshu (2006). "Boys as only-children and girls as only-children—parental gendered expectations of the only-child in the nuclear Chinese family in present-day China". Gender and Education. 18 (5): 491–505. doi:10.1080/09540250600881626. S2CID 144525986.
• Macleod, David I. (1982). "Act Your Age: Boyhood, Adolescence and the Rise of the Boy Scouts of America". Journal of Social History. 16 (2): 3–20. doi:10.1353/jsh/16.2.3.
• Mintz, Steven (2004). Huck's raft: A history of American childhood. Harvard UP. ISBN 9780674015081.
• Naka, Kansuke (2015). The Silver Spoon: Memoir of a Boyhood in Japan. Stone Bridge Press. ISBN 9781611720198.
• Plafker, Ted (2002). "Sex selection in China sees 117 boys born for every 100 girls". The BMJ. 324 (7348): 1233. doi:10.1136/bmj.324.7348.1233/a. PMC 1123206. PMID 12028966.
• Powell, Sacha; Smith, Kate, eds. (2017). An introduction to early childhood studies. Sage. ISBN 9781526417480.
• Rose, Clare (2016). Making, selling and wearing boys' clothes in late-Victorian England. Routledge. ISBN 9781138261860.
• Theriault, Daniel (2018). "A Socio-Historical Overview of Black Youth Development in the United States for Leisure Studies". International Journal of the Sociology of Leisure. 1 (2): 197–213. doi:10.1007/s41978-018-0013-y. S2CID 158309254.
• Van de Graaff, Kent M.; Fox, Stuart Ira (1989). Concepts of Human Anatomy and Physiology. Dubuque, Iowa: William C. Brown Publishers. ISBN 0697056759.
• Wainman, Ruth (2017). "'Engineering for Boys': Meccano and the Shaping of a Technical Vision of Boyhood in Twentieth-Century Britain". Cultural and Social History. 14 (3): 381–396. doi:10.1080/14780038.2017.1314581. S2CID 164528642.
• Wolff, Larry (1996). "The Boys Are Pickpockets, and the Girl Is a Prostitute": Gender and Juvenile Criminality in Early Victorian England from Oliver Twist to London Labour". New Literary History. 27 (2): 227–249. doi:10.1353/nlh.1996.0029. JSTOR 20057349. S2CID 162188050.

• Media related to Boys at Wikimedia Commons
• Quotations related to Boy at Wikiquote
• The dictionary definition of boy at Wiktionary
• Boyhood Studies, website and journal for the study of boys
• Historical Boys' Clothing