Article Date: 06 Jul 2009 – 1:00 PDT
Puberty is the period in children’s lives when they experience physical changes by which their bodies eventually become adult bodies that are capable of reproducing. Puberty is triggered by hormone signals from the brain to the ovaries and testes (gonads). The ovaries (in girls) and testes (in boys) respond to hormone signals from the brain by producing a range of hormones that stimulate the growth, function and change in various parts of the body, including the reproductive organs, breasts, skin, muscles, bones, hair and the brain.
According to Medilexicon’s medical dictionary, puberty is a “Sequence of events by which a child becomes a young adult, characterized by the beginning of gonadotropin secretion, gametogenesis, secretion of gonadal hormones, development of secondary sexual characteristics and reproductive functions; sexual dimorphism is accentuated. In girls, the first signs of normal puberty may be evident after age 8 with the process largely completed by age 16; in boys, normal puberty commonly begins at age 9 and is largely completed by age 18. Ethnic and geographic factors may influence the time at which various events typical of puberty occur.”
Growth is fast in the first half of puberty and stops when puberty is completed. Before puberty boys and girls are only different in having different genitalia (sex organs). During puberty several other differences between the sexes start to emerge, including body size, shape, composition and function development in several body systems and structure – we refer to the noticeable differences as secondary sex characteristics.
Puberty also includes the psychological and social changeover from childhood to adulthood. In this article the focus will be more on the physical aspects of puberty, rather than the psychological or social ones.
Many factors can contribute to exactly when puberty begins in a child, even stress. A study found that stress, such as that brought on by parental separation and absentee fathers, fast tracks puberty.
What is the difference between male and female puberty?
- Girls start puberty about one to two years earlier than boys.
- Girls’ generally complete puberty in a shorter time than boys.
- Girls reach adult height and reproductive maturity approximately 4 years after the physical changes of puberty appear.
- Boys continue to grow for about 6 years after the first visible changes of puberty.
- A girl’s puberty general spans from the ages of 9 to 14.
- A boy’s puberty generally spans from the ages of 10 to 17. Experts say this longer span is probably why adult males are generally taller than adult females.
- Testosterone and androgen are the main male sex steroids. Testosterone produces all male changes related to virilization, such as a deepened voice, facial hair and the development of muscles. Estradiol also plays a role in male development, but much more in female development.
- Estrogen and estradiol are the main hormones that drive female development. Estradiol promotes the growth of the uterus and breasts. Levels of estradiol rise earlier in girls than in boys, and also reach higher levels in women than in men. Testosterone is also involved in female development, but to a much smaller degree, compared to male development.