Puberty::journal    Title::girls    Pages::author    Volume::years    Issue::first    Which::growth

{{#invoke:redirect hatnote|redirect}} {{#invoke:redirect hatnote|redirect}} {{#invoke:Protection banner|main}} {{#invoke:Sidebar|sidebar}} Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction to enable fertilization. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the first half of puberty and is completed when the child has developed an adult body. Until the maturation of their reproductive capabilities, the pre-pubertal physical differences between boys and girls are the external sex organs.

On average, girls begin puberty at ages 10–11; boys at ages 11–12.<ref name="Kail">{{#invoke:citation/CS1|citation |CitationClass=book }}</ref><ref name="">"For girls, puberty begins around 10 or 11 years of age and ends around age 16. Boys enter puberty later than girls-usually around 12 years of age-and it lasts until around age 16 or 17." {{#invoke:citation/CS1|citation |CitationClass=news }}</ref> Girls usually complete puberty by ages 15–17,<ref><ref name="">{{#invoke:citation/CS1|citation |CitationClass=news }}</ref><ref name="Puberty">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> while boys usually complete puberty by ages 16–17.<ref><ref><ref name="Marshall17677">Marshall (1986), p. 176–7</ref> The major landmark of puberty for females is menarche, the onset of menstruation, which occurs on average between ages 12–13;<ref name="Tanner">(Tanner, 1990).</ref><ref name="U.S. menarche">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref><ref name="Canadian menarche">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref><ref name="UK menarche">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> for males, it is the first ejaculation, which occurs on average at age 13.<ref name="Jorgensen & Keiding">(Jorgensen & Keiding 1991).</ref> In the 21st century, the average age at which children, especially girls, reach puberty is lower compared to the 19th century, when it was 15 for girls and 16 for boys.<ref>{{#invoke:citation/CS1|citation |CitationClass=news }}</ref> This can be due to any number of factors, including improved nutrition resulting in rapid body growth, increased weight and fat deposition,<ref name="Guillette_2006">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> or exposure to endocrine disruptors such as xenoestrogens, which can at times be due to food consumption or other environmental factors.<ref name="Louis_2008">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref><ref name="Mouritsen_2010">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> Puberty which starts earlier than usual is known as precocious puberty. Puberty which starts later than usual is known as delayed puberty.

Notable among the morphologic changes in size, shape, composition, and functioning of the pubertal body, is the development of secondary sex characteristics, the "filling in" of the child's body; from girl to woman, from boy to man. Derived from the Latin puberatum (age of maturity), the word puberty describes the physical changes to sexual maturation, not the psychosocial and cultural maturation denoted by the term adolescent development in Western culture, wherein adolescence is the period of mental transition from childhood to adulthood, which overlaps much of the body's period of puberty.<ref>The Oxford Dictionary of English Etymology, C.T. Onions ed. Oxford University Press 1996 p. 720.</ref>

Puberty sections
Intro  Differences between male and female puberty  Puberty onset  Changes in males  Changes in females  Variations  Neurohormonal process  Stages  See also  References  Further reading  External links  

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