From the Guidelines
Puberty typically begins between ages 8-13 in girls and 9-14 in boys, following a predictable sequence of physical changes, with breast development (thelarche) being the first sign in girls around age 10-11, as supported by the study published in the Journal of Clinical Oncology 1. The sequence of changes in girls includes breast development, followed by pubic hair growth (pubarche), a growth spurt peaking around age 12, and finally menstruation (menarche) typically at age 12-13. In boys, the process begins with testicular enlargement around age 11-12, followed by pubic hair growth, penis enlargement, voice deepening, and a growth spurt that peaks around age 14, as described in various studies on pubertal development, including those referenced in Current Environmental Health Reports 1. These changes are triggered by hormonal shifts, primarily the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus, which stimulates the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as explained in the context of endocrine-disrupting chemicals and their effects on reproductive health 1. The timing and progression can vary significantly between individuals due to genetic factors, nutrition, and overall health status, highlighting the importance of considering these factors in the assessment and management of pubertal development, as noted in studies on the impact of environmental exposures on reproductive health 1. Key factors influencing the onset and progression of puberty include exposure to endocrine-disrupting chemicals, such as phthalates and bisphenol A, which have been associated with alterations in pubertal timing and reproductive development, as discussed in the study published in Current Environmental Health Reports 1. Understanding the normal sequence and timing of pubertal changes, as well as the potential impacts of environmental and genetic factors, is essential for the early identification and management of disorders of pubertal development, ensuring optimal outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Order of Changes in Puberty
The order of changes in puberty can vary between individuals, but generally follows a specific sequence.
- In girls, the first manifestation of puberty is breast development, which typically occurs between 8 to 13 years of age 2.
- Menarche, or the first menstrual period, usually occurs within 2 years of the onset of breast development, with a mean age of 12.8 years in American girls 2.
- In boys, the first sign of puberty is testicular enlargement, which normally occurs between 9 to 14 years of age 2.
- Pubic hair in boys typically appears 18 to 24 months after the onset of testicular growth 2.
Age-Related Changes
The age at which these changes occur can vary, but generally:
- Skeletal growth begins to increase in males at genital stage III and pubic-hair stage II, with peak height velocity attained at around 14 years in boys and 12 years in girls 2.
- Lean body mass, which primarily reflects muscle mass, begins to increase during early puberty in both boys and girls 2.
- Fat mass increases during the late stages of puberty in girls 2.
Hormonal Influences
Hormonal changes play a crucial role in the development of puberty:
- Gonadotropin-releasing hormone (GnRH) analogs can be used to treat central precocious puberty (CPP) and other childhood disorders affecting growth and puberty 3, 4.
- Testicular growth during puberty is rapid and mostly due to germ cell expansion and growth in seminiferous tubule diameter triggered by androgens 5.
- Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)/testosterone work in synergy and are both needed for normal spermatogenesis 5.