- Prepubertal children with constitutionally delayed puberty At least 2 years retardation of bone age Spontaneously progress into puberty within 1 year Boys: Testes long diameter 2.5-3.5 cm and plasma testosterone 40-300 ng/dL Girls: Breast development, but premenarcheal OR Hypogonadotropinism Delayed onset of pubertal milestones associated with anterior panhypopituitarism OR Kallman's syndrome No spontaneous progression into puberty within 2 years after 6 months replacement sex steroid treatment