Masculinity has its roots in genetics (see gender). Therefore while masculinity looks different in different cultures, there are common aspects to its definition across cultures. Sometimes gender scholars will use the phrase "hegemonic masculinity" to distinguish the most dominant form of masculinity from other variants. In the mid-twentieth century United States, for example, John Wayne might embody one form of masculinity, while Albert Einstein might be seen as masculine, but not in the same "hegemonic" fashion.
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 Latin and Sanskrit roots vir meaning man) reflect this. An association with physical and/or moral strength is implied. Masculinity is associated more commonly with adult men than with boys.
A great deal is now known about the development of masculine characteristics. The process of sexual differentiation specific to the reproductive system of Homo sapiens produces a female by default. The SRY gene on the Y chromosome, however, interferes with the default process, causing a chain of events that, all things being equal, leads to testes formation, androgen production and a range of both natal and post-natal hormonal effects covered by the terms masculinization or virilization. Because masculinization redirects biological processes from the default female route, it is more precisely called defeminization.
In many cultures displaying characteristics not typical to one's gender may become a social problem for the individual. Among men, some non-standard behaviors may be considered a sign of homosexuality, while a girl who exhibits masculine behavior is more frequently dismissed as a "tomboy". Within sociology such labeling and conditioning is known as gender assumptions and is a part of socialization to better match a culture's mores. The corresponding social condemnation of excessive masculinity may be expressed in terms such as "machismo" or "testosterone poisoning."
The relative importance of the roles of socialization and genetics in the development of masculinity continues to be debated. While social conditioning obviously plays a role, it can also be observed that certain aspects of the masculine identity exist in almost all human cultures.
The historical development of gender role is addressed by such fields as behavioral genetics, evolutionary psychology, human ecology and sociobiology. All human cultures seem to encourage the development of gender roles, through literature, costume and song. Some examples of this might include the epics of Homer, the King Arthur tales in English, the normative commentaries of Confucius or biographical studies of the prophet Muhammad. More specialized treatments of masculinity may be found in works such as the Bhagavad Gita or bushido's Hagakure.
Janet Saltzman Chafetz (1974, 35-36) describes seven areas of masculinity in general culture:
- Physical — virile, athletic, strong, brave. Unconcerned about appearance and aging;
- Functional — provider for family, defender of family from physical threat;
- Sexual — sexually aggressive, experienced. Single status acceptable;
- Emotional — unemotional, stoic, never crying;
- Intellectual — logical, intellectual, rational, objective, practical;
- Interpersonal — leader, dominating; disciplinarian; independent, free, individualistic; demanding;
- Other Personal Characteristics — success-oriented, ambitious, aggressive, competitive, proud, egotistical, moral, trustworthy; decisive, uninhibited, adventurous.
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.
Notwithstanding the personality gulf between men and women, the sex urge is sufficient to insure their coming together for the reproduction of the species. This instinct operated effectively long before humans experienced much of what was later called love, devotion, and marital loyalty. Mating is an innate propensity, and marriage is its evolutionary social repercussion.