Man

Overview
A man is a male human. The term man (irregular plural: men) is used for an adult human male, with the term boy being the usual term for a human male child or adolescent human male. However, man can refer to humanity as a whole.



Age and terminology
Manhood is the period in a male's life after he has transitioned from boyhood, at least physically, during puberty.

A boy is a male human child. For many, the word man implies a certain degree of maturity and responsibility that young men in particular often feel unprepared for; yet they may also feel too old to be called a boy. For this reason, many avoid using either man or boy to describe a young man and prefer colloquial terms such as bloke, lad, chap, fellow, guy or dude.

Biology and gender


Humans exhibit sexual dimorphism in many characteristics, many of which have no direct link to reproductive ability, however most of these characteristic 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. Some examples of male secondary sexual characteristics in humans, those acquired as boys become men or even later in life, are:
 * abdominal and chest hair
 * more hair on other parts of body
 * more facial hair
 * larger hands and feet than women
 * broader shoulders and chest
 * heavier skull and bone structure
 * greater muscle mass
 * a prominent Adam's apple and deep voice
 * fat deposits mainly around the abdomen and waist ("apple shape")
 * coarser skin texture

Reproductive system
The sex organs of a man are part of the reproductive system, consisting of the penis, testicles, vas deferens, and the prostate gland. 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 concept of fatherhood and family exists in human societies. The study of male reproduction and associated organs is called andrology.

Karyotype
The normal human karyotypes contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes. Normally karyotypes for men have both an X and a Y chromosome denoted 46,XY.

Illnesses
In general, men suffer from many of the same illnesses as women. Men generally tend to suffer from more illnesses than women but suffer from less sex-related illnesses than women. Men on average have a slightly lower life expectancy than women however the difference has generally reduced.

Circumcision
Around twenty percent of males world wide, particularly in the U.S., have been circumcised, wherein some or all of the foreskin is removed. However circumcision is also performed on some women, called female genital cutting.

Sexual characteristics
In humans, the sex of an individual is generally determined at the time of fertilization by the genetic material carried in the sperm cell. If a sperm cell carrying an X chromosome fertilizes the egg, the offspring will typically be female (XX); if a sperm cell carrying a Y chromosome fertilizes the egg, the offspring will typically be male (XY). This is referred to as the XY sex-determination system and is typical of most mammals, but quite a few other sex-determination systems exist, including some that are non-genetic. The term primary sexual characteristics denotes the kind of gamete the gonad produces: The ovary produces egg cells in the female, and the testis produces sperm cells in the male. The term secondary sexual characteristics denotes all other sexual distinctions that play indirect roles in uniting sperm and eggs. Secondary sexual characteristics include everything from the specialized male and female features of the genital tract, to the brilliant plumage of male birds or facial hair of humans, to behavioral features such as courtship.

Sex hormones
In mammals, the hormones that influence sexual differentiation and development are androgens (mainly testosterone), which stimulate later development of the ovary. In the sexually undifferentiated embryo, testosterone stimulates the development of the Wolffian ducts, the penis, and closure of the labioscrotal folds into the scrotum. Another significant hormone in sexual differeniation is the Anti-müllerian hormone, which inhibits development of the Müllerian ducts.

For males during puberty, testosterone, along with gonadotropins released by the pituitary gland, stimulates spermatogenesis, along with the full sexual distinction of a human male from a human female, while women are acted upon by estrogens and progesterones to produce their sexual distinction from the human male.

Masculinity
Enormous debate in Western societies has focused on perceived social, intellectual, or emotional differences between men and women. These differences are very difficult to quantify for both scientific and political reasons.

Characteristics


Janet Saltzman Chafetz (1974, 35-36) describes seven areas of masculinity in general culture:
 * 1) Physical -- virile, athletic, strong, brave. Unconcerned about appearance and aging;
 * 2) Functional -- breadwinner, provider for family as much as mate
 * 3) Sexual -- sexually aggressive, experienced. Single status acceptable;
 * 4) Emotional -- unemotional, stoic, never crying;
 * 5) Intellectual -- logical, intellectual, rational, objective, practical,
 * 6) Interpersonal -- leader, dominating; disciplinarian; independent, free, individualistic; demanding;
 * 7) Other Personal Characteristics -- success-oriented, ambitious, aggressive, proud, egotistical, ambitious; moral, trustworthy; decisive, competitive, uninhibited, adventurous.

Some of these differences have been supported by scientific research; others have not. It is especially difficult and contentious for science to separate the "innate" or biological differences from the learned or social differences. All should be considered broad generalizations; that is, at least a large minority of either gender would fit better with the other gender in any one of these aspects.

A number of the above stereotypes were not perceived in the same way as today (i.e., their applications to particular aspects and spheres of life, such as work vs. home) until the 19th century, beginning with industrialization.

In terms of outward appearance, few men in Western cultures wear cosmetics or clothing generally associated with female gender roles. (Doing so is generally stigmatized and viewed as cross-dressing.)

Culture and gender roles
Well into prehistoric culture, men are believed to have assumed a variety of social and cultural roles which are likely similar across many groups of humans. In hunter-gatherer societies, men were often if not exclusively responsible for all large game killed, the capture and raising of most or all domesticated animals, the building of permanent shelters, the defense of villages, and other tasks where the male physique and strong spatial-cognition were most useful. Some anthropologists believe that it may have been men who led the Neolithic Revolution and became the first pre-historical ranchers, as a possible result of their intimate knowledge of animal life.

Throughout history, the roles of men have changed greatly. As societies have moved away from agriculture as a primary source of jobs, the emphasis on male physical ability has waned. Traditional gender roles for working men typically involved jobs emphasizing moderate to hard manual labor (see Blue-collar worker), often with no hope for increase in wage or position. For poorer men among the working classes the need to support their families, especially during periods of industrial change and economic decline, forced them to stay in dangerous jobs working long arduous hours, often without retirement. Many industrialized countries have seen a shift to jobs which are less physically demanding, with a general reduction in the percentage of manual labor needed in the work force (see White-collar worker). The male goal in these circumstances is often of pursuing a quality education and securing a dependable, often office-environment, source of income. The Men's Movement is in part a struggle for the recognition of equality of opportunity with women, and for equal rights irrespective of gender, even if special relations and conditions are willingly incurred under the form of partnership involved in marriage. The difficulties of obtaining this recognition are due to the habits and customs recent history has produced. Through a combination of economic changes and the efforts of the feminist movement in recent decades, men in some societies now compete with women for jobs that traditionally excluded women. Some larger corporations have instituted tracking systems to try to ensure that jobs are filled based on merit and not just on traditional gender selection. Assumptions and expectations based on sex roles both benefit and harm men in Western society (as they do women, but in different ways) in the workplace as well as on the topics of education, violence, health care, politics, and fatherhood - to name a few. Research has identified anti-male sexism in some areas (a concept which must be distinguished and differentiated from the traditional anti-female sexism in its ubiquity and impact) which can result in what appear to be unfair advantages given to women.

The Parsons model was used to contrast and illustrate extreme positions on gender roles. Model A describes total separation of male and female roles, while Model B describes the complete dissolution of barriers between gender roles. The examples are based on the context of the culture and infrastructure of the United States. However, these extreme positions are rarely found in reality; actual behavior of individuals is usually somewhere between these poles. The most common 'model' followed in real life in the United States and Great Britain is the 'model of double burden'.