Adolescence is the transitional stage of development from child to adult. The word derives from the Latin verb adolescere meaning, literally, “to begin to be smelly.” As the name suggests, the time is identified with dramatic changes in the body, along with developments in a person’s psychology and academic career. In the onset of adolescence, children usually completeelementary school and enter secondary education, such as middle school or high school.
During this period of life, most children go through the physical stages of puberty, which often begin before a person has reached the age of 13. Most cultures regard people as becoming adults at various ages of the teenage years. Many cultures have a formal age of majority when adolescents formally become adults. For example, Japan’s celebration of this in January is called the coming of age (or 成人式) (see Japanese calendar).
Puberty, occurring during adolescence, is the stage in the human lifespan when a child begins to develop adult secondary sex characteristics as their hormone balance shifts towards an adult state. Briefly, this is caused by the hypothalamus gland that secretes hormones into the blood stream which trigger growth in the gonads: the girl’s ovaries and the boy’s testicles. In femaleadolescents, the first menstrual period is called menarche.
In developed countries, the age at puberty has reduced in the last century, primarily because of better nutrition. That change is particularly apparent in the countries that adopted western food such as Japan. Girls tend to go through puberty earlier than boys.