Man

A man is an adult male human.[a][2][3] 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, scrotum, testicles, sperm duct, prostate gland and the epididymis, and by secondary sex characteristics, including a narrower pelvis, narrower hips, and smaller breasts.

Throughout human history, traditional gender roles 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 rates. Many religious doctrines stipulate certain rules for men, such as religious circumcision. Men are over-represented as both perpetrators and victims of violence.

Trans men have a gender identity that does not align with their female sex assignment at birth, while intersex 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 root *man- (see Sanskrit/Avestan manu-, Slavic mǫž "man, male").[4] 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 compounds "werewolf" (from Old English werewulf, literally "man-wolf"), and "wergild", literally "man-payment".[5][6][7]

Biology

In humans, sperm cells carry either an X or a Y sex chromosome. If a sperm cell carrying a Y chromosome fertilizes the female ovum, 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.[8]

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.

Adult humans exhibit sexual dimorphism 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.[9]

Secondary sex characteristics are features that appear during puberty in humans.[10][11] 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.[12][13][14] Secondary sexual characteristics that are specific to men include:

Broadened shoulders;[15]

Increased body hair;

An enlarged larynx (also known as an Adam's apple);[15] and

A voice that is significantly deeper than the voice of a child or a woman.[13]

Men weigh more than women.[16] On average, men are taller than women by about 10%.[16] On average, men have a larger waist in comparison to their hips (see waist–hip ratio) than women. In women, the index and ring fingers tend to be either more similar in size or their index finger is slightly longer than their ring finger, whereas men's ring finger tends to be longer.[17]