Man

A man is an adult male human.[1][2] Prior to adulthood, a male human is referred to as a boy (a male child or adolescent). Like most other male mammals, a man's genome 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 characteristics, 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, which includes the penis, testicles, sperm duct, prostate gland and the epididymis, as well as secondary sex characteristics.

The English term "man" is derived from the Proto-Indo-European root *man- (see Sanskrit/Avestan manu-, Slavic mǫž "man, male").[3] 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. Mann only came to mean "man" in Middle English, replacing wer, which survives today only in the compound "werewolf" (from Old English werwulf, literally "man-wolf").[4][5]

In humans, sperm cells normally carry either an X or a Y sex chromosome. If a sperm cell carrying a Y chromosome fertilizes the female ova, the offspring will be male (XY). The SRY gene is normally found on the Y chromosome and is the testis determining factor that governs male sex differentiation . Sex differentiation in males proceeds in a testes dependent way while female differentiation is not gonad dependent.[6]

Humans exhibit sexual dimorphism in many characteristics, many of which have no direct link to reproductive ability, although most of these characteristics do have a role in sexual attraction. Most expressions of sexual dimorphism in humans are found in height, weight, and body structure, though there are always examples that do not follow the overall pattern. For example, men tend to be taller than women, but there are many people of both sexes who are in the mid-height range for the species.

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 penis and testicles. Secondary sex characteristics are features that appear during puberty in humans.[7][8] Such features are especially evident in the sexually dimorphic phenotypic traits that distinguish between the sexes, but—unlike the primary sex characteristics—are not directly part of the reproductive system.[9][10][11] Secondary sexual characteristics that are specific to men include:

The male reproductive system includes external and internal genitalia. The male external genitalia consist of the penis, the male urethra, and the scrotum, while the male internal genitalia consist of the testes, the prostate, the epididymis, the seminal vesicle, the vas deferens, the ejaculatory duct, and the bulbourethral gland.[14]

The male reproductive system's function is to produce semen, which carries sperm and thus genetic information that can unite with an egg within a woman. Since sperm that enters a woman's uterus and then fallopian tubes goes on to fertilize an egg which develops into a fetus or child, the male reproductive system plays no necessary role during the gestation. The study of male reproduction and associated organs is called andrology.

Testosterone stimulates the development of the Wolffian ducts, the penis, and closure of the labioscrotal folds into the scrotum. Another significant hormone in sexual differentiation is the anti-Müllerian hormone, which inhibits the development of the Müllerian ducts. For males during puberty, testosterone, along with gonadotropins released by the pituitary gland, stimulates spermatogenesis.

Men have lower life expectancy[15] and higher suicide rates[16] compared to women.

Male sexuality and attraction vary from person to person, and a man's sexual behavior can be affected by many factors, including evolved predispositions, personality, upbringing, and culture. While the majority of men are heterosexual, significant minorities are homosexual or bisexual.[17]

Trans men have a male gender identity that does not align with their female sex assignment at birth and may undergo masculinizing hormone replacement therapy and/or sex reassignment surgery, while intersex men may have sex characteristics that do not fit typical notions of male biology.[18] A 2016 systemic review estimated that 0.256% of people self-identify as female-to-male transgender.[19] A 2017 survey of 80,929 Minnesota students found that roughly twice as many female-assigned adolescents self-identified as transgender, compared to adolescents with a male sex assignment.[20]

Masculinity (also sometimes called manhood or manliness) is a set of attributes, behaviors, and roles associated with boys and men. Although masculinity is socially constructed,[21] some research indicates that some behaviors considered masculine are biologically influenced.[22] To what extent masculinity is biologically or socially influenced is subject to debate.[22] It is distinct from the definition of the biological male sex, as both males and females can exhibit masculine traits.[23]

Standards of manliness or masculinity vary across different cultures and historical periods.[24] While the outward signs of masculinity look different in different cultures, there are some common aspects to its definition across cultures. In all cultures in the past, and still among traditional and non-Western cultures, getting married is the most common and definitive distinction between boyhood and manhood.[25] In the late 20th century, some qualities traditionally associated with marriage (such as the "triple Ps" of protecting, providing, and procreating) were still considered signs of having achieved manhood.[25][26]

Anthropology has shown that masculinity itself has social status, just like wealth, race and social class. In Western culture, for example, greater masculinity usually brings greater social status. Many English words such as virtue and virile (from the Indo-European root vir meaning man) reflect this.[27][28]

The Mars symbol (♂) is a common symbol that represents the male sex.[29] The symbol is identical to the planetary symbol of Mars.[30] It was first used to denote sex by Carl Linnaeus in 1751. The symbol is sometimes seen as a stylized representation of the shield and spear of the Roman god Mars. According to Stearn, however, this derivation is "fanciful" and all the historical evidence favours "the conclusion of the French classical scholar Claude de Saumaise (Salmasius, 1588–1683)" that it is derived from θρ, the contraction of a Greek name for the planet Mars, which is Thouros.[31]