A man is an adult

male Male (Mars symbol, symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot sexual reproduction, repro ...

human. Prior to adulthood, a male human is referred to as a

boy 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 described as a man. Definition, etymology, and use According to the ''Merriam-Webster Dictionary'', a boy is "a ...

(a male child or adolescent). Like most other male mammals, a man's

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...

usually inherits an X chromosome from the mother and a Y chromosome from the father. Sex differentiation of the male fetus is governed by the SRY gene on the Y chromosome. During puberty, hormones which stimulate androgen production result in the development of

secondary sexual characteristic Secondary sex characteristics are features that appear during puberty in humans, and at sexual maturity in other animals. These characteristics are particularly evident in the sexually dimorphic phenotypic traits that distinguish the sexes of a ...

s, thus exhibiting greater differences between the sexes. These include greater muscle mass, the growth of facial hair and a lower body fat composition. Male anatomy is distinguished from female anatomy by the

male reproductive system The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body and within the pelvis. The main male sex organs are the penis and the t ...

, which includes the

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...

testicle A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testostero ...

sperm duct The vas deferens or ductus deferens is part of the male reproductive system of many vertebrates. The ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. The vas deferens is a partially coiled tube ...

prostate gland The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and physi ...

and the

epididymis The epididymis (; plural: epididymides or ) is a tube that connects a testicle to a vas deferens in the male reproductive system. It is a single, narrow, tightly-coiled tube in adult humans, in length. It serves as an interconnection between t ...

, and by

secondary sex characteristic Secondary sex characteristics are features that appear during puberty in humans, and at sexual maturity in other animals. These characteristics are particularly evident in the sexually dimorphic phenotypic traits that distinguish the sexes of ...

s, including a narrower pelvis, narrower hips, and smaller

breast The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues. In females, it serves as the mammary gland, which produces and s ...

s without

mammary gland A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in pr ...

s. Throughout

human history Human history, also called world history, is the narrative of humanity's past. It is understood and studied through anthropology, archaeology, genetics, and linguistics. Since the invention of writing, human history has been studied t ...

, traditional

gender role A gender role, also known as a sex role, is a social role encompassing a range of behaviors and attitudes that are generally considered acceptable, appropriate, or desirable for a person based on that person's sex. Gender roles are usually cen ...

s have often defined and limited men's activities and opportunities. Men often face conscription into military service or are directed into professions with high

mortality rate Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of d ...

s, resulting in a shorter life expectancy than women. Many religious doctrines stipulate certain rules for men, such as

forced circumcision Forced circumcision is the circumcision of men and children against their will. In a biblical context, the term is used especially in relation to Paul the Apostle and his polemics against the circumcision controversy in early Christianity. ...

. Men are over-represented as both perpetrators and

victims of violence Victim(s) or The Victim may refer to: People * Crime victim * Victim, in psychotherapy, a posited role in the Karpman drama triangle model of transactional analysis Films and television * ''The Victim'' (1916 film), an American silent film by t ...

Trans men A trans man is a man who was assigned female at birth. The label of transgender man is not always interchangeable with that of transsexual man, although the two labels are often used in this way. ''Transgender'' is an umbrella term that in ...

have a

gender identity Gender identity is the personal sense of one's own gender. Gender identity can correlate with a person's assigned sex or can differ from it. In most individuals, the various biological determinants of sex are congruent, and consistent with the ...

that does not align with their female

sex assignment Sex assignment (sometimes known as gender assignment) is the discernment of an infant's sex at or before birth. A relative, midwife, nurse or physician inspects the external genitalia when the baby is delivered and, in more than 99.95% of ...

at birth, while

intersex Intersex people are individuals born with any of several sex characteristics including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical b ...

men may have sex characteristics that do not fit typical notions of male biology.

Etymology

The English term "man" is derived from the

Proto-Indo-European Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo- ...

root ''*man-'' (see

Sanskrit Sanskrit (; attributively , ; nominalization, nominally , , ) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in South Asia after its predecessor languages had Trans-cul ...

Avestan Avestan (), or historically Zend, is an umbrella term for two Old Iranian languages: Old Avestan (spoken in the 2nd millennium BCE) and Younger Avestan (spoken in the 1st millennium BCE). They are known only from their conjoined use as the scri ...

''manu-'', Slavic ''mǫž'' "man, male"). More directly, the word derives from Old English '' mann''. The Old English form primarily meant "person" or "human being" and referred to men, women, and children alike. The Old English word for "man" as distinct from "woman" or "child" was ''

wer WER or Wer may refer to: * Weak echo region, in meteorology, an area of markedly lower reflectivity within thunderstorms resulting from an increase in updraft strength * Word error rate, in computational linguistics, a common metric of measur ...

''. ''Mann'' only came to mean "man" in Middle English, replacing ''wer'', which survives today only in the compounds "

werewolf In folklore, a werewolf (), or occasionally lycanthrope (; ; uk, Вовкулака, Vovkulaka), is an individual that can shapeshift into a wolf (or, especially in modern film, a therianthropic hybrid wolf-like creature), either purposel ...

" (from Old English '' werwulf'', literally "man-wolf"), and "

wergild Weregild (also spelled wergild, wergeld (in archaic/historical usage of English), weregeld, etc.), also known as man price ( blood money), was a precept in some archaic legal codes whereby a monetary value was established for a person's life, to ...

", literally "man-payment".

Biology

In humans, sperm cells carry either an X or a Y sex chromosome. If a sperm cell carrying a

Y chromosome The Y chromosome is one of two sex chromosomes ( allosomes) in therian mammals, including humans, and many other animals. The other is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or a ...

fertilizes the female

ovum The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete i ...

, the offspring will have a male karyotype (XY). The SRY gene is typically found on the Y chromosome and causes the development of the testes, which in turn govern other aspects of male sex differentiation. Sex differentiation in males proceeds in a testes-dependent way while female differentiation is not gonad dependent. Primary sex characteristics (or sex organs) are characteristics that are present at birth and are integral to the reproductive process. For men, primary sex characteristics include the

and

s. Adult humans exhibit

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...

in many other characteristics, many of which have no direct link to reproductive ability. Humans are sexually dimorphic in body size, body structure, and body composition. Men tend to be taller and heavier than women, and adjusted for height, men tend to have greater lean and bone mass than women, and lower fat mass. Secondary sex characteristics are features that appear during

puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a b ...

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

s. Such features are especially evident in the

sexually dimorphic Sexual dimorphism is the condition where the sexes of the s