Adult - Biological Adulthood

Biological Adulthood

Historically and cross-culturally, adulthood has been determined primarily by the start of puberty (the appearance of secondary sex characteristics such as menstruation in women, ejaculation in men, and pubic hair in both sexes). In the past, a person usually moved from the status of child directly to the status of adult, often with this shift being marked by some type of coming-of-age test or ceremony.

Most medical and general English dictionaries define childhood as the period from infancy to puberty, thus historically adulthood began with puberty. After the social construct of adolescence was created, adulthood split into two forms: biological adulthood and social adulthood. Thus, there are now two primary forms of adults: biological adults (people who have attained reproductive ability, are fertile, or who evidence secondary sex characteristics) and social adults (people who are recognized by their culture and/or law as being adults). Depending on the context, adult can indicate either definition.

Although few or no established dictionaries provide a definition for the two word term biological adult, the first definition of adult in multiple dictionaries includes "the stage of the life cycle of an animal after reproductive capacity has been attained". Thus, the base definition of the word adult is the period beginning at puberty. Although this is the primary definition of the base word adult, the two word term biological adult stresses or clarifies that the original definition, based on the beginning of puberty, is being used (that is, the organism has matured to the biologically important point of being able to reproduce).

Although there is no scientific agreement on when physical maturation completes, in modern society social adulthood somewhat corresponds to the completion of physical maturation. Because the term adult is most often used without the adjective social or biological, and since the term is frequently used to refer to social adults, some writers have taken the meaning of the two word phrase biological adult to begin at the end of physical maturation rather than the onset of puberty.

In modern developed countries, puberty and therefore biological adulthood generally begins around 10 or 11 years of age for girls and 12 or 13 years of age for boys, though this will vary from person to person.