Variants of Pubertal Progression

Abstract

Delayed puberty is defined as the absence of testicular enlargement in boys or breast development in girls 2 to 2.5 standard deviations (SDs) later than the population average. Although a single definition does not apply to all populations, a practical definition for girls is the lack of breast development by age 13 years and for boys, a testicular volume of less than 4 mL by 14 years.1–3 Because of a downward trend in pubertal timing in the United States4,5 and other countries6,7 and differences in pubertal timing among ethnic groups, some advocate for updated definitions with younger age cutoffs for the general population, or perhaps for particular countries or ethnic groups. Development of pubic hair is usually not considered in the definition because pubarche may result from maturation of the adrenal glands (adrenarche), and onset of pubic hair can be independent of hypothalamic-pituitary-gonadal (HPG) axis activation...